リリース

NATS server v2.14.3 is a maintenance release dominated by JetStream, MQTT and clustering bug fixes, with two MQTT fixes closing pre-auth memory exhaustion and panic conditions and one breaking change: JSONP monitoring support has been removed.

• securityMQTT memory exhaustion and panic fixes

  Applies to servers exposing MQTT. Fixed in v2.14.3: malformed partial CONNECT packets could exhaust pre-auth memory, and a PUBLISH remaining-length underflow could panic the server. Upgrade if you run MQTT, especially with untrusted or public clients.

• breakingJSONP monitoring support removed

  Applies to deployments relying on JSONP callbacks against monitoring endpoints (e.g. /varz, /connz via callback= param). This is removed in v2.14.3; switch dashboards or scripts to plain JSON polling before upgrading.

• breakingPermission checks tightened for leaf trace destination and NoAuthUser

  Applies to leaf node setups using Nats-Trace-Dest, and to accounts using NoAuthUser. Fixed in v2.14.3: leaf connections could bypass Nats-Trace-Dest publish permission checks, and NoAuthUser did not enforce connection restrictions. Review permission and NoAuthUser configs after upgrading, since previously permitted traffic may now be denied as intended.

v2.12.12 is a bugfix and hardening release for nats-server, centered on numerous JetStream/Raft data-integrity and panic fixes plus removal of JSONP support from monitoring endpoints. No CVEs are disclosed, but several fixes close memory-exhaustion and panic paths reachable via malformed MQTT input that operators should treat as security-relevant.

• securityMQTT partial-CONNECT and PUBLISH-underflow crash/DoS fixes

  If you run MQTT, upgrade to fix two memory-exhaustion/panic paths: partial CONNECT packets could exhaust pre-authentication memory, and PUBLISH remaining-length underflow could panic the server. Both are exploitable by unauthenticated clients sending malformed input.

• securityInteger-overflow panics fixed in monitoring and JetStream usage tracking

  CONNZ/SUBSZ pagination previously could panic on integer overflow, and JetStream remote usage updates could panic on length integer overflow. Operators with large clusters or heavy monitoring polling should upgrade to remove these panic-inducing edge cases.

• breakingJSONP support removed from monitoring endpoints

  JSONP callback support has been removed from monitoring endpoints in v2.12.12, unconditionally. Any tooling or dashboards that rely on JSONP callbacks against /varz, /connz, or similar endpoints will break and must switch to plain JSON requests.

Istio 1.29.5 is a security release fixing 14 Envoy CVEs under ISTIO-SECURITY-2026-005, with several rated HIGH (DoS, crash, use-after-free). It also repairs a gateway revision-label traffic outage, an ambient ipset health-probe gap, a krt memory leak, and a multicluster controller panic.

• security14 Envoy CVEs fixed (max severity HIGH) — ISTIO-SECURITY-2026-005

  All 14 Envoy CVEs under ISTIO-SECURITY-2026-005 are fixed in 1.29.5. The highest-severity issues include an HTTP/3 QPACK decoding DoS (GHSA-p7C7-7c47-pwch), a compressed-payload inflation bypass of MaxInflateRatio (CVE-2026-48044), a %REQUESTED_SERVER_NAME% formatter crash (CVE-2026-47220), a QUIC content-length validation issue guarded by envoy.reloadable_features.quic_validate_headers_only_content_length (CVE-2026-48743), and a PROXY protocol TLV length mismatch (CVE-2026-47692). Upgrade all 1.29.x deployments to 1.29.5.

• securityOAuth2 filter padding oracle in AES-256-CBC cookie decryption (CVE-2026-47775)

  Operators using the OAuth2 filter with AES-256-CBC cookie encryption should upgrade immediately. The filter now supports AES-256-GCM with a gcm. algorithm marker; plan migration away from AES-256-CBC after upgrading.

• securityext_authz use-after-free with per-route service overrides (CVE-2026-47205)

  Clusters using ext_authz with per-route service overrides are exposed to a use-after-free crash when a downstream connection resets during an in-flight authorization check (CVE-2026-47205). Upgrade to 1.29.5 to eliminate the crash window.

• breakingJSON nesting depth limit reduced to 1000 (CVE-2026-48042)

  JSON parser nesting depth is now capped at 1000 by default (down from 10000). If any Envoy configuration relies on deeper nesting, the old limit can be restored temporarily by setting the runtime flag envoy.reloadable_features.limit_json_parser_nesting_depth to false, but plan to eliminate deep nesting.

Istio 1.30.2 is a security-plus-bugfix patch release, its main content is fixes for 14 Envoy CVEs (one high-severity HTTP/3 DoS via QPACK, others medium to high) under ISTIO-SECURITY-2026-005, alongside operator-relevant changes to pilot-agent metric merging and new AuthorizationPolicy trust-domain fields.

• security14 Envoy CVEs fixed under ISTIO-SECURITY-2026-005, several high severity

  Applies to all 1.30.x deployments. Fixed a DoS in the HTTP/3 stack via QPACK blocked decoding, plus a JSON parser change limiting nesting depth to 1000 (previously the 10K fallback is reachable only if envoy.reloadable_features.limit_json_parser_nesting_depth is set to false) and a headers-only content-length validation fix gated by envoy.reloadable_features.quic_validate_headers_only_content_length. Upgrade to 1.30.2.

• securityMultiple use-after-free and crash fixes across ext_authz, ext_proc, gRPC stats, and OAuth2 filters

  Applies when ext_authz per-route service overrides are active and a downstream connection resets mid-authorization-check (CVE-2026-47205), or when ext_proc/gRPC stats/OAuth2 filters are in use. Upgrade to close use-after-free and padding-oracle issues; the OAuth2 filter now also supports AES-256-GCM cookie encryption via a gcm. marker.

• breakingpilot-agent metric merging now rejects protobuf content type

  Applies to deployments using pilot-agent metric merging (PILOT_AGENT_MERGE_ENVOY_STATS). Allowed content types are now restricted to text/plain and application/openmetrics-text; protobuf-based scraping of merged metrics will break. Check scrape configs before upgrading.

• enhancementAuthorizationPolicy gains trust-domain matching

  Applies to AuthorizationPolicy authors who want mTLS trust-domain-based access control. New trustDomains and notTrustDomains fields on Source let policies match or exclude requests by the trust domain in the peer certificate.

Envoy v1.38.3 is a security-only release patching 15 CVEs plus one upstream wasmtime CVE. Two issues are rated critical: a TLS SAN NUL-byte auth bypass (CVE-2026-47778) and HTTP/3-to-HTTP/1 request smuggling (CVE-2026-48743); the remaining 13 are rated high, covering crashes, a zip-bomb DoS, a PKCE padding oracle, a 65 KB upstream data spillover, and a heap buffer overflow.

• securityCRITICAL: TLS SAN NUL-byte auth bypass (CVE-2026-47778)

  CVE-2026-47778 (GHSA-f8x4-rw5x-f3r7): a NUL byte embedded in a TLS SAN causes truncation during comparison, allowing an attacker to bypass certificate-based authentication. Upgrade to v1.38.3 unconditionally.

• securityCRITICAL: HTTP/3 to HTTP/1 request smuggling (CVE-2026-48743)

  CVE-2026-48743 (GHSA-8phg-2h2q-jgxf): a headers-only HTTP/3 request carrying a nonzero Content-Length can be smuggled into a downstream HTTP/1 backend. Any deployment proxying HTTP/3 to HTTP/1 is affected. Upgrade to v1.38.3.

• securityHIGH: PROXY Protocol v2 upstream data spillover (CVE-2026-47692)

  CVE-2026-47692 (GHSA-wh36-hm39-mm3r): the PROXY Protocol v2 header generator leaks "skipped" TLVs, spilling up to 65 KB of attacker-controlled data into the upstream application stream. Upgrade to v1.38.3.

• breakingIntel DLB connection balancer extension removed

  The contrib extension envoy.network.connection_balance.dlb (Intel DLB connection balancer) has been disabled at the Bazel build layer in v1.38.3 due to a broken source archive. Any deployment that relied on this extension must migrate to an alternative connection balancer.

• breakingTLS certificate Brotli compression now disabled by default

  The runtime guard envoy.reloadable_features.tls_certificate_compression_brotli is now disabled by default. When off, QUIC uses zlib-only certificate compression and TCP TLS performs no certificate compression. If you depended on Brotli compression for TLS certificates, re-enable this flag explicitly after upgrading.

Envoy v1.37.5 is a security-only release fixing 15 Envoy CVEs/GHSAs and one upstream dependency CVE, with severities reaching critical. Three critical issues stand out: HTTP/3-to-HTTP/1 request smuggling, TLS SAN auth bypass via embedded NUL bytes, and a PROXY Protocol v2 spillover that puts attacker-controlled data into upstream streams. All v1.37.x deployments should upgrade without delay.

• securityCritical: HTTP/3 to HTTP/1 request smuggling (CVE-2026-48743)

  CVE-2026-48743 (GHSA-8phg-2h2q-jgxf): HTTP/3 requests with headers-only and a nonzero Content-Length can smuggle requests into HTTP/1 upstream connections. Applies to any deployment terminating HTTP/3 and proxying to HTTP/1 backends. Upgrade immediately.

• securityCritical: TLS SAN NUL-byte auth bypass (CVE-2026-47778)

  CVE-2026-47778 (GHSA-f8x4-rw5x-f3r7): A TLS SAN containing an embedded NUL byte is truncated at that byte during comparison, allowing a certificate to match patterns it should not. Any deployment making auth decisions based on TLS SAN validation is affected. Upgrade immediately.

• securityCritical: PROXY Protocol v2 TLV spillover into upstream stream (CVE-2026-47692)

  CVE-2026-47692 (GHSA-wh36-hm39-mm3r): The PROXY Protocol v2 header generator emits TLVs that were supposed to be skipped, spilling up to 65 KB of attacker-controlled data into the upstream application stream. Affects deployments that generate PROXY Protocol v2 headers toward upstreams. Upgrade immediately.

• securityHigh: Two OAuth2 filter vulnerabilities (padding oracle + UAF)

  CVE-2026-47775 and CVE-2026-48090 (GHSA-396h-jpq4-vc7p, GHSA-3cj2-c63f-q26f): The OAuth2 filter has a PKCE code-verifier padding oracle and a use-after-free risk when an async token fetch completes after stream teardown. Both affect deployments using envoy.filters.http.oauth2.

• securityHigh: HTTP/3 QPACK blocked-decoding DoS (GHSA-p7c7-7c47-pwch)

  HTTP/3 QPACK blocked decoding (GHSA-p7c7-7c47-pwch) can be exploited to cause a DoS against the HTTP/3 stack. Affects any deployment serving HTTP/3.

• securityHigh: grpc_stats filter segfault on Connect protocol (CVE-2026-47204)

  CVE-2026-47204 (GHSA-3jxh-8p6x-7pf6): The grpc_stats filter segfaults on Connect-protocol requests routed to direct_response routes. Affects deployments using envoy.filters.http.grpc_stats.

• breakingIntel DLB connection balancer contrib extension disabled at build time

  The envoy.network.connection_balance.dlb contrib extension (Intel DLB connection balancer) has been disabled at the Bazel build layer across all platforms due to a source archive breakage. Deployments relying on this extension must pursue a local workaround or alternative balancing strategy until the source issue is resolved.

Envoy v1.36.9 is a security-only release patching 15 CVEs (2 rated critical, the rest high or medium) across TLS SAN handling, HTTP/3, PROXY protocol, JSON parsing, OAuth2, ext_proc, grpc_stats, zstd, DNS, and statsd. Operators should upgrade immediately, as two of the vulnerabilities -- TLS SAN auth bypass and HTTP/3 request smuggling -- are unconditional or broadly exploitable.

• securityCRITICAL: TLS SAN NUL-byte auth bypass (CVE-2026-47778 / GHSA-f8x4-rw5x-f3r7)

  A TLS SAN containing an embedded NUL byte causes the SAN to be truncated, bypassing certificate-based authentication checks. All deployments are affected. Upgrade to v1.36.9 immediately.

• securityCRITICAL: HTTP/3-to-HTTP/1 request smuggling (CVE-2026-48743 / GHSA-8phg-2h2q-jgxf)

  A headers-only HTTP/3 request with a nonzero Content-Length can be smuggled into HTTP/1 backends, enabling request smuggling attacks. Affects any deployment proxying HTTP/3 to HTTP/1 backends.

• securityHIGH: PROXY Protocol v2 upstream data spillover (CVE-2026-47692 / GHSA-wh36-hm39-mm3r)

  PROXY Protocol v2 header generation leaks up to 65 KB of attacker-controlled data into the upstream application stream via improperly emitted TLVs. Affects deployments using the PROXY Protocol v2 header generator.

• securityHIGH: Stack overflow on deeply nested JSON (CVE-2026-48042 / GHSA-f24p-rxw2-g6pv)

  Deeply nested JSON input triggers a stack overflow in the object destructor, crashing the proxy. All deployments are affected.

• securityHIGH: wasmtime dependency CVE (CVE-2026-47261)

  The wasmtime dependency was bumped to resolve CVE-2026-47261. All deployments using Wasm extensions are affected.

• breakingDLB connection balancer extension disabled (capability removed)

  The contrib Intel DLB connection balancer extension (envoy.network.connection_balance.dlb) is now disabled at the Bazel layer for all platforms due to a source archive breakage. Builds that previously enabled this extension will lose it silently.

Envoy v1.35.13 is a major security release fixing 13 CVEs, two of them critical: a PROXY protocol v2 TLV spillover leaking up to 65KB into the upstream stream, and a TLS SAN NUL-truncation bug that can bypass certificate-based auth. It also disables the contrib Intel DLB connection balancer extension due to a build breakage.

• securityPROXY Protocol v2 TLV spillover (CVE-2026-47692)

  Applies to all v1.35.13 deployments running PROXY protocol v2 header generation upstream. CVE-2026-47692 lets an attacker's "skipped" TLVs leak up to 65KB into the upstream application stream. Upgrade immediately if you use this feature.

• securityTLS SAN NUL truncation enables auth bypass (CVE-2026-47778)

  Applies to deployments validating client certificates by SAN. CVE-2026-47778 lets an embedded NUL byte in a TLS SAN truncate the parsed name, allowing certificates to match unintended hostnames and bypass authentication. Upgrade immediately.

• security11 more high-severity CVEs across core filters and HTTP/3

  Eleven additional high-severity CVEs are fixed across ext_proc, router internal redirects, OAuth2 (two separate issues: padding oracle and a use-after-free from late async token completion), zstd decompression, grpc_stats, JSON parsing, the DNS filter, HTTP/3 (content-length validation and a separate QPACK-based DoS), and TcpStatsdSync. Each is a crash, DoS, or memory-safety bug tied to a specific filter or codec; upgrade to pick up all fixes, or check which filters you run to prioritize.

• securityWasmtime dependency bump fixes CVE-2026-47261

  A separate wasmtime CVE (CVE-2026-47261) is fixed by bumping the com_github_wasmtime dependency. Applies to deployments using the Wasm filter.

• breakingIntel DLB connection balancer extension disabled

  The contrib extension envoy.network.connection_balance.dlb (Intel DLB connection balancer) is disabled at the Bazel build layer for all builds and platforms due to a source archive breakage. Anyone building Envoy with this extension enabled needs an alternate connection balancer.

Strimzi 1.0.1 patches two CVEs and disables cross-namespace Entity Operator watching by default. The v1-only CRD API requirement from 1.0.0 remains enforced — no v1beta2/v1beta1/v1alpha1.

• securityPatch two CVEs — upgrade promptly

  CVE-2026-55225 and CVE-2026-55226 are fixed in 1.0.1. Details are in the Strimzi security advisories. Given both are fixed in the same patch release, treat this as a security-motivated upgrade and prioritize it over waiting for a convenient maintenance window.

• breakingEnable cross-namespace watching explicitly if you use watchedNamespace

  If your Kafka CR's Entity Operator section has watchedNamespace set to a namespace different from the Kafka cluster's namespace, the Topic or User Operator will stop watching it after upgrading. Before or immediately after upgrading, set STRIMZI_ENTITY_OPERATOR_WATCHED_NAMESPACE_ENABLED=true in your Cluster Operator deployment. Check all Kafka CRs across namespaces — missing this will silently break topic/user reconciliation.

• breakingComplete CRD migration to v1 before upgrading

  Strimzi 1.0.1 (like 1.0.0) only accepts v1 CRDs. If you skipped the migration step when moving to 1.0.0, or if you are upgrading from an older release directly, run the CRD conversion procedure documented in the Strimzi 1.0.1 deploying guide before applying the new operator manifests. Applying the operator without converted CRDs will cause reconciliation failures.

Cilium 1.18.11 is a patch release focused on stability, fixing memory leaks, socket handling crashes, and Gateway API routing bugs. No breaking changes; safe to adopt for teams running 1.18.x in production.

• securityApply patch if you see agent crashes in socket handling

  Cilium 1.18.11 fixes a nil pointer dereference in filterAndDestroySockets that could crash the agent. If you have seen sudden agent pod restarts or panic logs mentioning socket filtering, upgrade promptly. This is a stability issue that affects 1.18.10 and earlier.

• breakingVerify MTU settings on non-Cilium interfaces after upgrade

  1.18.11 changes MTU handling to skip interfaces not managed by Cilium. If your infrastructure depends on Cilium adjusting MTU on external interfaces (e.g., host-managed veth pairs), test this upgrade in a staging environment first. Mark interfaces with altname to ensure they are recognized as Cilium-owned; otherwise, MTU will not be modified.

• enhancementAdopt if running Kubernetes Gateway API with TLS routes

  This patch fixes two distinct bugs in Gateway API support: weighted backend routing for TLSRoute passthrough and mixed listener handling. If you use Gateway API with TLS termination or passthrough, this upgrade eliminates silent routing failures. No configuration changes needed; test existing Gateway API resources in a staging cluster first.

Linkerd edge-26.6.2 patches policy and profile validation bugs, tightens namespace restrictions on external workloads, and upgrades to Envoy proxy v2.357.0 with unified failure accrual tuning.

• securityProfile validation now rejects nil configs

  The nil check in profile validation closes a path to crashes on malformed configs. No immediate action needed, but if your automation generates profiles programmatically, ensure they always have valid structure before applying them.

• breakingNamespace-restricted external workloads may affect routing

  External workloads and endpoints now honor namespace boundaries. If you cross namespaces with external workloads in your Linkerd setup, verify routing still works after upgrade. Update any policies that rely on previous (unrestricted) cross-namespace access.

• enhancementTune load balancing with unified failure accrual

  Unified failure accrual and response-penalty load biasing gives you finer control over how proxies handle slow or failing endpoints. Test this in a canary namespace first—adjust failure thresholds and penalty weights to match your SLOs. Check Linkerd docs for new policy knobs.

Istio 1.29.4 patches a high-severity DoS CVE in Envoy plus six bug fixes, including a critical ambient mode traffic routing bug that could silently send traffic to unhealthy endpoints cluster-wide.

• securityPatch CVE-2026-47774 immediately — unauthenticated HTTP/2 DoS

  CVE-2026-47774 lets any unauthenticated attacker exhaust Envoy's memory via crafted HTTP/2 requests. Cookie header bytes aren't fully counted in header size validation, and HPACK limits apply only to encoded bytes — not decoded totals. If you're on 1.29.x, upgrade to 1.29.4 now. This is exploitable from outside the mesh wherever Envoy terminates HTTP/2, including ingress gateways.

• breakingAmbient mode users: audit Services using publishNotReadyAddresses + traffic distribution

  If any Service in your ambient mesh combines publishNotReadyAddresses:true with PreferSameZone or PreferSameNode traffic distribution, every other Service sharing that traffic-distribution preset was receiving healthPolicy:AllowAll — meaning traffic could route to not-ready endpoints across the entire cluster. After upgrading to 1.29.4, verify endpoint health policies are correct. Check ztunnel logs for unexpected AllowAll entries before and after the upgrade to confirm the fix took effect.

• enhancementCNI on older kernels: nftables fallback now automatic

  Hosts running an nft binary compiled without JSON support were causing the CNI agent to log errors and retry indefinitely on every pod removal — a silent drain on the agent's reliability. The new startup check detects this and switches to iptables automatically. No action needed for most users, but if you've been seeing 'JSON support not compiled-in' errors in CNI agent logs, this fix resolves the root cause.

Istio 1.28.8 patches a high-severity DoS CVE in Envoy's HTTP/2 memory handling, plus three bug fixes covering TLS delivery, route filter status reporting, and a nasty ambient mode health policy contamination bug.

• securityPatch CVE-2026-47774 immediately if you expose HTTP/2 endpoints

  An unauthenticated attacker can crash your Envoy sidecars by sending specially crafted HTTP/2 requests that bypass header size validation — cookie bytes aren't counted properly, and HPACK limits apply only to encoded size, not decoded. Any cluster accepting external or untrusted HTTP/2 traffic is at risk. Upgrade to 1.28.8 now. If you can't upgrade immediately, consider adding Envoy-level request header size limits or WAF rules to filter malformed HTTP/2 frames as a temporary measure.

• breakingAudit ambient mode clusters using publishNotReadyAddresses with zonal traffic distribution

  If you run ambient mode and any Service sets publishNotReadyAddresses:true alongside PreferSameZone or PreferSameNode, you've likely been routing traffic to not-ready endpoints across your entire cluster — not just for that Service, but for every Service sharing the same traffic-distribution preset. This is a silent data-plane correctness bug. After upgrading, verify endpoint health behavior across affected Services and check whether any downstream systems received traffic from unhealthy pods during the window this was active.

• enhancementFix for silent route filter drops enables reliable config debugging

  Previously, HTTPRoute or GRPCRoute filters with invalid header values would vanish from Envoy config without any status signal — making it nearly impossible to diagnose why traffic wasn't behaving as expected. Now Istio reports an invalid filter status, which surfaces in the Gateway API resource status. After upgrading, re-check any routes you may have debugged by guesswork; the explicit status message will clarify whether a header filter was rejected.

Istio 1.30.1 patches a high-severity DoS CVE in Envoy's HTTP/2 handling plus fixes 13 bugs including a CNI agent panic, a traffic distribution poison bug, and a consistent hash load balancing regression.

• securityPatch CVE-2026-47774 immediately — unauthenticated HTTP/2 DoS

  An attacker can exhaust Envoy's memory using crafted HTTP/2 requests that exploit gaps in Cookie header accounting and HPACK decoded-size limits. No authentication required. If you're running any Istio 1.30.x version, upgrade to 1.30.1 now. Check whether your ingress gateways are exposed to untrusted traffic — those are the highest-risk surfaces.

• breakingAmbient users with traffic distribution policies: audit Services immediately

  If you use ambient mode with any Service that sets publishNotReadyAddresses: true alongside PreferSameZone or PreferSameNode traffic distribution, the bug caused ztunnel to apply healthPolicy: AllowAll to OTHER unrelated Services sharing that preset. This means traffic has potentially been routed to not-ready endpoints across your cluster. After upgrading to 1.30.1, verify endpoint health state and check whether any unexpected traffic reached unready pods.

• enhancementRun 'istioctl analyze' after upgrading to catch stale Gateway API CRDs

  Upgrading Istio without updating Gateway API CRDs was silently breaking TLS passthrough in 1.30.0 — istiod would filter resources without any visible error. The new IST0176 check surfaces this. After upgrading, run istioctl analyze and resolve any IST0176 findings before they cause silent routing failures in production.

v1.38.1 is a security-focused patch addressing two HTTP/2 CVEs and two oauth2 vulnerabilities — upgrade immediately if running HTTP/2 or oauth2 filter.

• securityPatch HTTP/2 and oauth2 CVEs now — don't wait for your next maintenance window

  Two HTTP/2 CVEs (cookie-bomb memory exhaustion via HPACK and nghttp2 CVE-2026-27135) plus two oauth2 bugs (timing oracle and a crash-as-auth-bypass) make this a must-apply patch. If you're running the oauth2 filter, the HMAC timing side-channel is particularly nasty — attackers could probe HMAC secret validity over time. Upgrade to v1.38.1 immediately. The new HTTP/2 header limit behavior is enabled by default; only revert with `envoy.reloadable_features.http2_include_cookies_in_limits` if you have a specific, documented reason.

• breakingUpstream failure reason stripped from HTTP response bodies — check your client error handling

  Any downstream client or API consumer that parses or displays the upstream transport failure reason from the HTTP response body will now get nothing. The information is still in access logs. Audit your clients and dashboards before upgrading — if something depends on that response body content, you have a short window to either update the client or re-enable the old behavior with `envoy.reloadable_features.hide_transport_failure_reason_in_response_body`.

• breakingEDS batch LB rebuild coalescing is now opt-in — test under high-churn service discovery

  Load balancer rebuild coalescing during EDS batch host updates is disabled by default. Environments with large EDS clusters and frequent host churn (e.g., Kubernetes rolling deployments with many pods) may see increased CPU from more frequent LB rebuilds. Benchmark your control-plane interaction patterns after upgrading. Re-enable the old behavior with `envoy.reloadable_features.coalesce_lb_rebuilds_on_batch_update` if you observe performance regression.

v1.37.3 is a security-focused patch fixing two HTTP/2 CVEs and oauth2 vulnerabilities — upgrade immediately if you use HTTP/2 or oauth2 filter.

• securityPatch HTTP/2 deployments now for CVE-2026-47774 and CVE-2026-27135

  Two HTTP/2 CVEs are fixed in this release. CVE-2026-47774 enables a cookie-bomb attack that causes excessive memory usage by sending large numbers of cookies that bypass header size limits before this fix. CVE-2026-27135 is an nghttp2-level vulnerability. If you terminate HTTP/2 traffic, upgrade to v1.37.3 immediately. The new cookie-counting behavior is enabled by default; if it causes regressions, you can temporarily disable it with the feature flag `envoy.reloadable_features.http2_include_cookies_in_limits`, but treat that as a short-term workaround only.

• securityRotate oauth2 HMAC secrets after upgrading

  The timing side-channel in HMAC verification means a patient attacker could have probed whether a given secret was valid. After upgrading, rotate your oauth2 HMAC secrets as a precaution — especially in internet-facing deployments. The AES-CBC crash fix is also relevant: the previous 1/256 spurious decryption success could cause unpredictable auth behavior, not just crashes.

• breakingCookie-heavy workloads may see HTTP/2 stream resets

  The CVE-2026-47774 fix changes how cookies are counted against `mutable_max_request_headers_kb` and `max_headers_count`. Clients sending many cookies that were previously accepted may now hit limits and receive stream resets. Test your high-cookie traffic patterns in staging before rolling this to production, and review your header size limits to ensure they are set appropriately for your workloads.

v1.36.7 is a security-focused patch addressing two CVEs in HTTP/2 and an HPACK cookie-bomb attack vector in the oauth2 filter, plus a crash fix. Upgrade immediately.

• securityPatch HTTP/2 CVEs now — two CVEs affect any HTTP/2-exposed Envoy

  CVE-2026-47774 enables a cookie-bomb attack where crafted HPACK-compressed cookies inflate to exhaust Envoy memory. After patching, cookies count toward `mutable_max_request_headers_kb` and `max_headers_count`. If you see legitimate requests being reset post-upgrade, the escape hatch is the `envoy.reloadable_features.http2_include_cookies_in_limits` flag — but audit your header size limits first rather than disabling the protection. CVE-2026-27135 is an nghttp2-layer fix with no workaround; you must upgrade.

• securityAudit oauth2 filter deployments for timing and decryption exposure

  Two oauth2 bugs fixed here are subtle but serious. The timing side-channel in HMAC verification could allow an attacker to probe secret validity over many requests. The AES-CBC crash (1/256 chance on bad tokens) is a reliability issue that could be triggered deliberately. If you use the oauth2 filter with token cookies, treat this as a high-priority upgrade — there's no configuration workaround for either issue.

• breakingReview header size limits before deploying — cookie counting is a behavior change

  Cookies previously excluded from header size accounting now count toward limits. In practice, applications with many or large cookies may hit `max_headers_count` or `mutable_max_request_headers_kb` and get HTTP/2 stream resets where they didn't before. Before rolling out, check your current limit configurations against real traffic cookie sizes. If you need time, the reloadable feature flag lets you defer the behavior change, but don't leave it disabled long-term.

v1.35.11 is a security-focused patch fixing two HTTP/2 CVEs and two oauth2 vulnerabilities — upgrade immediately if you're running HTTP/2 or oauth2 filter.

• securityPatch HTTP/2 HPACK cookie-bomb vulnerability now

  CVE-2026-47774 allows an attacker to craft requests with large numbers of HPACK-compressed cookies that decompress into massive header payloads, causing excessive memory usage. The fix resets offending streams and counts cookies toward existing header size limits. Roll out this patch to any Envoy instance terminating HTTP/2 traffic. If you hit legitimate regressions with cookie-heavy workloads, the flag `envoy.reloadable_features.http2_include_cookies_in_limits` can temporarily revert the behavior — but treat that as a short-term workaround, not a solution.

• securityUpgrade if you use the oauth2 filter — two separate fixes here

  There are two distinct oauth2 issues fixed: a timing side-channel in HMAC verification (exploitable via repeated probing to determine secret validity) and a crash from incorrect AES-CBC decryption behavior on secret mismatch. The crash was probabilistic (~1/256 per request) but real. If your deployment uses Envoy's built-in oauth2 filter for token validation, this patch directly reduces both crash risk and secret exposure surface.

• enhancementEvaluate stats eviction for high-cardinality metric environments

  The new `stats_eviction_interval` config allows Envoy to periodically purge unused metrics from memory. If you're running workloads with dynamic or high-cardinality labels (e.g., per-request or per-user stats), this can meaningfully reduce memory footprint over time. Test in staging first — eviction behavior depends on whether extensions implement the evictable metrics interface, so not all metrics will be affected.

NATS v2.14.2 is a focused stability release fixing multiple JetStream data integrity issues, lock release bugs, and protocol corruption risks — upgrade if you run JetStream at any meaningful scale.

• securityProtocol corruption vectors closed — critical for WebSocket and JetStream users

  Two protocol corruption bugs were fixed: one in $JS.ACK subject rewriting and one in compressed WebSocket client buffer handling. Either could produce malformed frames that corrupt stream state or client sessions. If you expose NATS WebSocket endpoints or rely heavily on JetStream ACKs, treat this as a security-adjacent stability issue and prioritize the upgrade.

• breakingTwo separate lock-release bugs can cause silent hangs — patch now

  Both the filestore and consumer code paths had cases where locks were never released after specific error conditions (write errors and start sequence errors). In production this means stuck consumers or hung filestore operations that don't recover without a restart. If you've seen unexplained JetStream stalls, this is likely why. Upgrade to v2.14.2 immediately.

• enhancementHigh subject-count streams no longer risk CPU spikes — no config change needed

  The filestore block skip check was triggering runaway CPU on streams with very high subject counts. The fix is automatic after upgrade — no configuration changes required. If you've been working around this with stream design compromises (e.g., artificially limiting subjects per stream), you can revisit those decisions after upgrading.

v2.12.10 is a focused bug-fix release addressing protocol corruption risks, JetStream Raft/quorum issues, and a CPU runaway bug in high-cardinality streams.

• securityUpdate x/crypto and nkeys immediately

  This release bumps golang.org/x/crypto to v0.52.0 and nkeys to v0.4.16. These libraries handle cryptographic operations in NATS auth flows. Don't wait for scheduled maintenance — patch now, especially if your clusters are internet-exposed or use decentralized auth.

• breakingProtocol corruption fixes require prompt upgrade for WebSocket and JetStream users

  Two separate protocol-level corruption bugs are fixed here: one in compressed WebSocket clients, one in $JS.ACK subject rewriting. Either can silently corrupt message framing. If you run WebSocket clients or any JetStream workload with acknowledgements, staying on 2.12.9 or earlier is a real risk. Upgrade servers first, then clients.

• enhancementHigh-cardinality JetStream streams get a CPU safety fix — verify your config

  The block skip check on streams with very high subject counts could cause runaway CPU. That check is now disabled for those cases. If you've been seeing unexpected CPU spikes on JetStream nodes with streams containing millions of subjects, this is likely the culprit. After upgrading, also review Counter stream and message schedule configs — new constraints are enforced that may reject previously accepted but incorrect configurations.

NATS v2.14.1 is a substantial patch release fixing ~30 bugs across JetStream, clustering, and core messaging — several of them data-integrity and panic-level issues worth deploying promptly.

• securitygolang.org/x/crypto bumped to v0.51.0 — update now if you embed nats-server

  The x/crypto and x/sys dependency updates often carry CVE fixes. If you embed nats-server as a Go library (common in edge/IoT deployments), rebuild and redeploy. For standard deployments, just upgrade the binary. Don't sit on this one — crypto library updates in a messaging server are not optional hygiene.

• breakingReview the 2.14 Upgrade Guide before deploying — 2.13.x was skipped

  The release notes explicitly reference backwards-compatibility notes against 2.12.x, not 2.13.x, because that minor version was never released. If your team is running 2.12.x and skipped 2.13.x, read the 2.14 upgrade guide carefully before rolling out. Pay attention to JetStream consumer and stream API changes that may affect your clients.

• enhancementUse the new client-traffic /varz metrics for baseline observability

  The four new metrics (in/out client msgs/bytes) give you a cleaner split between client traffic and internal cluster/leafnode chatter. Wire these into your Prometheus scrape or monitoring dashboard now to establish baselines. This is especially useful for capacity planning on servers that handle mixed client and cluster traffic, since previously you had to infer client load from total metrics.

v2.12.9 is a dense bug-fix release targeting JetStream stability — covering Raft correctness, consumer state corruption, and filestore encryption bugs that could silently corrupt data.

• securityUpdate: golang.org/x/crypto bumped to v0.51.0

  The x/crypto dependency was updated alongside Go 1.25.10. If your org tracks CVEs against transitive dependencies, verify your SBOM tooling picks this up. Upgrade to v2.12.9 to pull in the patched crypto library — there's no workaround at the application level.

• breakingEncrypted JetStream users must upgrade — filestore corruption risk

  A bug in filestore encryption mode conversion could cause block-level corruption when switching encryption settings (PR #8105, #8166). If you've ever changed encryption mode on an existing stream, inspect those streams after upgrading. If corruption already occurred, you'll need to restore from a pre-conversion snapshot.

• enhancementUse the new /varz client traffic metrics for capacity planning

  The four new metrics (in/out_client_msgs and in/out_client_bytes) let you separate actual client-facing load from internal cluster/leafnode traffic. Wire these into your Prometheus scrape now — they're directly useful for right-sizing clusters and spotting noisy clients without needing to parse per-connection data.

Emissary-Ingress v4.1.0 ships Envoy 1.37.2 and fixes a stale cache bug that caused Istio mTLS cert rotation to silently fail.

• securityReview Envoy 1.37.x release notes before upgrading

  This upgrade spans Envoy 1.37.0 through 1.37.2, which includes security patches and potentially deprecated xDS fields. Pull up the Envoy 1.37.0, 1.37.1, and 1.37.2 changelogs and scan for any deprecated API fields or behavior changes that match your current Mapping/Ambassador configs before rolling out to production.

• breakingStale config cache fix may change startup behavior

  The IR.check_deltas fix now triggers a full reconfigure when an empty-delta snapshot arrives with a cached state. In practice this means Emissary will re-push config to Envoy in scenarios where it previously did nothing. If you have automation or health checks that depend on the old (broken) quiet behavior during cert rotation windows, validate them in staging first.

• enhancementUpgrade if you run Emissary alongside Istio

  If your cluster uses Istio and Emissary together, this fix directly addresses mTLS cert rotation failures (issue #4744). Stale certificates staying in the cache caused silent connectivity breakage during rotation events. Upgrading to v4.1.0 should eliminate those intermittent failures without any config changes on your part.

Istio 1.29.3 patches two security vulnerabilities — an AuthorizationPolicy bypass and a cross-namespace XDS config leak — alongside a multicluster deadlock fix and AWS EKS ambient mesh probe fix.

• securityAudit AuthorizationPolicy rules using suffix-match principals or namespace selectors — patch immediately

  Regex metacharacters (., [, etc.) in source.principals and source.namespaces were embedded into Envoy SafeRegex unescaped. This means a policy allowing 'spiffe://cluster.local/ns/foo/sa/bar.admin' could inadvertently also match 'spiffe://cluster.local/ns/foo/sa/barXadmin'. Any service with suffix-based wildcard principal matching is potentially affected. Upgrade to 1.29.3 and review policies where principals or namespace values contain dots, brackets, or other regex metacharacters.

• securityRotate access controls on XDS debug endpoints — any authenticated workload could read cross-namespace configs

  The /debug/syncz and /debug/config_dump endpoints served by StatusGen had no namespace boundary enforcement. An authenticated workload in namespace A could enumerate and read Envoy configs of workloads in namespace B. If you run multi-tenant clusters or expose istiod debug endpoints, assume cross-namespace config data may have been accessible. Upgrade immediately and audit who has accessed these endpoints via your API server audit logs.

• breakingMulti-cluster operators: the secret controller deadlock fix may change behavior during cluster updates

  The deadlock in the multicluster secret controller was triggered during remote cluster updates. If your control plane has been experiencing hangs or stalls in multi-cluster scenarios, this fix resolves the root cause — but test your cluster join/leave workflows after upgrading to confirm expected behavior is restored.

Native sidecars promoted to GA and enabled by default, plus a security fix restricting Server resources from affecting workloads outside their namespace. Heavy dependency refresh across Rust and Go stacks.

• securityServer namespace isolation fix — review cross-namespace Server resources immediately

  A fix was applied so that Server resources can no longer affect workloads in namespaces other than their own. If you have intentionally or accidentally created Server policies that were influencing workloads cross-namespace, those policies will silently stop applying after this upgrade. Audit your Server resources across all namespaces and verify that authorization policies still behave as expected post-upgrade. The risk of misconfigured over-broad policies is reduced, but any reliance on the previous behavior will break.

• breakingNative sidecars are now on by default — audit your cluster before upgrading

  Native sidecar support (using Kubernetes init containers with restartPolicy: Always) is now GA and enabled by default. If your cluster runs Kubernetes < 1.29, native sidecars are unsupported and this will break injection. Even on supported versions, verify that any tooling, admission webhooks, or pod lifecycle assumptions in your workloads are compatible. Test in a staging environment before rolling out to production. If you need the old behavior, explicitly disable the feature flag during install/upgrade.

• enhancementConfigure honorTimestamps on the linkerd-proxy PodMonitor

  If you're using the Prometheus Operator and have timestamp alignment issues in your Linkerd proxy metrics (e.g., stale or out-of-order samples), you can now set honorTimestamps in the Helm chart for the linkerd-proxy PodMonitor. This is a quality-of-life win for teams with strict metric ingestion pipelines. Set it explicitly during your next Helm upgrade rather than leaving it at the default.

Cilium v1.19.4 is a stability-focused patch release with 20+ bug fixes covering crash prevention, IPsec reliability, and Cluster Mesh correctness — upgrade if you run any of those features.

• securityUpdate moby/spdystream dependency (security fix included)

  This release bumps github.com/moby/spdystream to v0.5.1 as a security fix. The dependency is used in Kubernetes API communication paths. No CVE number is listed in the release notes, but treat this as a prompt to upgrade — staying on v1.19.3 leaves the exposure open.

• breakingHand-managed EndpointSlices need service-proxy-name label added

  If you set --k8s-service-proxy-name and manage EndpointSlices manually, those slices will now be filtered OUT at the watch level unless they carry the matching service.kubernetes.io/service-proxy-name label. After upgrading, any untagged hand-managed slice becomes invisible to Cilium, causing traffic drops. Audit your EndpointSlices before upgrading and stamp the label on any that are missing it.

• enhancementPrioritize upgrade if you run IPsec, WireGuard, or Cluster Mesh

  Three distinct data-plane reliability fixes land here: IPsec packet drops during rolling key rotation, WireGuard silent packet loss under constrained MTU with IPv6, and Cluster Mesh missing backends for multi-port services. Any of these can cause hard-to-diagnose intermittent connectivity issues. If your environment uses any of these features, this patch should move to the front of your upgrade queue.

v1.17.16 patches a cross-namespace traffic hijacking vulnerability in CiliumLocalRedirectPolicy, fixes an IPsec panic on malformed input, and resolves a static pod identity resolution bug.

• securityAudit LRP addressMatcher configs before upgrading

  The LRP addressMatcher change fixes a real attack vector: a policy in one namespace could previously override a Service frontend and redirect traffic cross-namespace. After upgrading, any LRP that was relying on this override behavior will stop working silently — traffic won't redirect as expected. Before upgrading, audit your CiliumLocalRedirectPolicy objects for addressMatcher entries that overlap with existing Service frontends. If you legitimately need the old behavior, set --enable-lrp-address-matcher-override=true, but treat that as a temporary measure and redesign the policy.

• securityUpgrade if running IPsec — agent crash risk on malformed input

  The parseSPI panic means a malformed IPsec packet could crash the Cilium agent, taking down networking on that node. This is a low-complexity denial-of-service risk for any cluster using Cilium's IPsec transparent encryption. Upgrade to v1.17.16 promptly if IPsec is enabled in your environment.

• breakingLRP addressMatcher behavior change is not fully backward-compatible

  This is a behavior change, not just a bug fix. If you have CiliumLocalRedirectPolicies using addressMatcher that overlap with Service ClusterIPs or external IPs, those policies will now be rejected or ignored where they previously worked. Test your LRP configurations in a non-production environment before rolling this upgrade out. The opt-in flag --enable-lrp-address-matcher-override=true exists, but using it means you are accepting the previously-vulnerable behavior.

Cilium v1.18.10 is a stability-focused patch release fixing agent crashes, IPsec panics, Cluster Mesh backend gaps, and a data race in IPAM — all backported from upstream.

• securitymoby/spdystream and x/net security updates are included

  This release pulls in a security fix for github.com/moby/spdystream and bumps x/net to v0.53. Both are network-layer dependencies. If your policy or threat model tracks transitive dependency CVEs, this patch justifies the upgrade on its own.

• breakingUpgrade encrypted clusters to fix IPsec panic risk

  A panic in parseSPI on malformed IPsec input could crash the agent on nodes running encrypted traffic. If you use IPsec encryption, treat this as a priority upgrade — a malformed packet or misconfigured peer can take down the agent process entirely.

• enhancementCluster Mesh users with shared target ports should upgrade

  The missing global service backends bug silently dropped backends from services where multiple ports mapped to the same target port. Traffic would route correctly within a single cluster but fail cross-cluster. Upgrade and verify affected services post-rollout using hubble observe or service endpoint inspection.

A routine edge release dominated by dependency bumps, with two meaningful bug fixes: multicluster service cleanup now respects namespaces, and a CLI gateway API version correction.

• securityRust TLS stack updated — aws-lc-rs, rustls-webpki, rustls-pki-types all bumped

  Several TLS-adjacent crates were updated in one shot: aws-lc-rs 1.16.3, rustls-webpki 0.103.13, and rustls-pki-types 1.14.1. No CVEs are called out explicitly, but these are the cryptographic underpinnings of Linkerd's mTLS. If you're in a security-sensitive environment, this is a good reason to pull this edge over older ones.

• breakingKubernetes 1.31 is now the minimum supported version

  The MSKV bump to 1.31 means clusters running 1.30 or older are no longer in the supported envelope. Check your cluster versions before adopting this edge release — if you're still on 1.30, upgrade Kubernetes first or hold on this Linkerd edge.

• enhancementFix multicluster namespace-scoped service cleanup before upgrading

  If you run Linkerd multicluster and have services spread across multiple namespaces, the previous cleanup logic could operate beyond its intended namespace scope. This fix is a correctness improvement — after upgrading, verify your mirrored services are in the expected state, especially if you've seen unexpected service deletions or stale mirrors in non-default namespaces.

NATS v2.12.8 is a substantial bug-fix release targeting JetStream stability — particularly clustered stream/consumer reliability, Raft edge cases, and a bearer JWT disclosure vulnerability in the monitoring API.

• securityPatch immediately: /connz was leaking bearer JWTs

  Any deployment using JWT-based auth with the monitoring endpoint exposed (even internally) was potentially leaking bearer tokens in /connz responses. Rotate any JWTs that may have been exposed, audit monitoring endpoint access logs, and upgrade to v2.12.8 now. If you can't upgrade immediately, restrict /connz access via firewall or NATS monitoring auth.

• securityCLI argument secrets now redacted in monitoring

  Route and cluster URLs passed as CLI arguments (which often contain credentials) were previously visible in monitoring output. Upgrade to v2.12.8 and review any monitoring dashboards or log aggregation pipelines that may have captured this data historically.

• enhancementJetStream cluster operators: test your scaling and recovery paths

  This release fixes several nasty edge cases — stream leader catch-up from snapshots, Raft commit index resets on term mismatches, in-flight assignment visibility for stream/consumer info, and the 'last sequence mismatch' error from failed proposals. If you've been seeing any of these intermittent errors in clustered JetStream, v2.12.8 is a high-priority upgrade. After upgrading, monitor for reduced error rates in stream info and consumer info endpoints during scaling operations.

NATS v2.11.17 is a security and stability patch addressing JWT bearer token exposure in monitoring endpoints, credential redaction gaps, and several crash/correctness bugs.

• securityPatch immediately: /connz was leaking bearer JWTs

  Any operator exposing the NATS monitoring port (default 8222) to internal or external networks should treat this as urgent. Bearer tokens visible in /connz could be harvested and replayed. Rotate any JWTs that may have been exposed, audit who had access to your monitoring endpoints, and upgrade to 2.11.17 now. If you cannot upgrade immediately, firewall the monitoring port.

• securityCLI-embedded secrets were visible in monitoring output

  If your NATS deployment passes route or cluster URLs with embedded credentials as command-line arguments, those secrets were previously visible in monitoring output. Audit your monitoring data for any historical exposure, rotate affected credentials, and upgrade. Long-term, prefer config files or environment-based secret injection over CLI arguments.

• breakingRepeated CONNECT behavior change may affect edge-case clients

  The fix for repeated CONNECT messages clearing subscriptions changes previously tolerated (but incorrect) behavior. Custom clients or unusual connection patterns that send multiple CONNECT messages on the same connection could see subscriptions unexpectedly dropped. Audit any non-standard client code before upgrading in production.

Maintenance-heavy edge release with OpenSSL/rustls security bumps, a policy admission fix for Gateway routes, and a more robust annotation-to-metric-label conversion in the injector.

• securityPick up OpenSSL and rustls-webpki patches now

  Two OpenSSL crate bumps landed in this release, plus a rustls-webpki update. These sit in the proxy's TLS stack. If you're running any Linkerd edge build in a security-sensitive environment, upgrade to edge-26.4.4 to get the patched cryptographic dependencies rather than waiting for the next stable.

• breakingVerify Gateway route policies after the admission webhook fix

  The admission webhook previously ran full validation on Gateway routes even when they contained fields Linkerd doesn't support, causing legitimate routes to be rejected. That's fixed now — but if you worked around this by restructuring routes, review whether those workarounds are still needed or are now masking misconfigurations.

• enhancementTest chart override behavior if you use custom install values

  The fix to apply overrides to chart values on install closes a gap where certain Helm value overrides weren't being applied. If you have installation automation that relies on specific override patterns, run a dry-run install against this version to confirm the resulting values match expectations before rolling to production.

Envoy v1.38 is a massive release with several breaking changes requiring immediate action — RSA key usage enforcement, BoringSSL build flag changes, and tcp_proxy config validation are the top priorities before upgrading.

• securityPatch CVE-2026-27135 by upgrading to v1.38

  This release includes the nghttp2 patch for CVE-2026-27135, which affects HTTP/2 header field handling. If you're running Envoy as an HTTP/2 gateway or proxy, this is a direct exposure. Prioritize upgrading clusters that terminate or proxy HTTP/2 traffic. RBAC header matcher also received a fix preventing concatenation-based bypass attacks — another reason to treat this upgrade as security-relevant.

• breakingAudit TLS configs before upgrading — RSA key usage now enforced

  enforce_rsa_key_usage defaults to true starting this release and will be removed entirely next release, making it permanent. Any upstream TLS connection where the certificate's key usage doesn't match the negotiated cipher will be rejected. Before upgrading, audit your upstream certificate configurations. Test in staging first — silent failures in prod will be connection resets, not helpful error messages.

• breakingUpdate BoringSSL FIPS build pipelines before building v1.38

  The --define=boringssl=fips Bazel flag is gone. CI/CD pipelines or Dockerfiles that build Envoy with FIPS mode will fail silently or error out. Replace with --config=boringssl-fips. If you're consuming official binaries rather than building from source, this doesn't affect you directly, but verify your supply-chain tooling if you maintain custom builds.

• enhancementOpenTelemetry metrics over HTTP — drop the collector sidecar

  The OTel stat sink can now push metrics directly via OTLP/HTTP without requiring a collector sidecar. If you're running otel-collector as a DaemonSet purely for Envoy metrics forwarding, you can simplify that architecture. Evaluate whether direct OTLP/HTTP export to your backend (Grafana Cloud, Honeycomb, etc.) reduces operational overhead in your environment.

v1.33.4 is a security-critical patch fixing a Lua code injection CVE in Contour's Cookie Rewriting feature — upgrade immediately, and note the hard Envoy 1.35.0 minimum requirement.

• securityPatch CVE-2026-41246 immediately — arbitrary code execution risk in shared Envoy

  Any tenant with RBAC permissions to create or modify HTTPProxy resources could inject arbitrary Lua code through a crafted pathRewrite value. In multi-tenant clusters where Envoy is shared infrastructure, this means a compromised or malicious tenant could steal xDS client credentials or deny service to other tenants. Upgrade Contour to v1.33.4 and ensure Envoy is at 1.35.0 or later before deploying. Audit your RBAC policies to limit HTTPProxy write access to trusted principals as a defense-in-depth measure.

• breakingEnvoy 1.35.0 minimum — verify your Envoy version before upgrading Contour

  This release will not function correctly with Envoy versions older than 1.35.0 due to the new filterContext-based Lua approach. If you manage your own Envoy image or pin versions, upgrade Envoy first. The bundled Envoy in the official manifests is already at v1.35.10, so if you use the standard deployment you're covered — but custom or air-gapped environments need explicit attention here.

• enhancementReview HTTPProxy RBAC regardless of upgrade timing

  Even after patching, the underlying attack surface is broad write access to HTTPProxy resources. Take this as a signal to tighten RBAC: restrict HTTPProxy creation/modification to platform operators rather than application developers where possible. In high-trust multi-tenant environments this kind of privilege separation is the right long-term control.

v1.32.5 is a security patch fixing a Lua code injection vulnerability (CVE-2026-41246) in Contour's Cookie Rewriting feature, plus an Envoy bump to v1.34.14. Upgrade immediately in multi-tenant environments.

• securityPatch CVE-2026-41246 immediately in multi-tenant clusters

  Any cluster where untrusted users or teams have RBAC permissions to create or modify HTTPProxy resources is directly exposed. An attacker crafts a pathRewrite.value that breaks out of the Lua string context, gaining code execution in Envoy — which runs as shared infrastructure. That means credential theft (xDS client certs) or denial of service for every tenant on the same Envoy instance. Upgrade to v1.32.5 now. While you prepare the upgrade, audit who has create/update rights on HTTPProxy and tighten RBAC to the minimum necessary.

• breakingReview existing cookieRewritePolicies after upgrade

  The fix adds escaping to pathRewrite.value inputs. Legitimate values with special characters (backslashes, quotes, etc.) will now be escaped before Lua interpolation, which changes runtime behavior. Test any HTTPProxy resources using cookieRewritePolicies[].pathRewrite.value in a staging environment post-upgrade to confirm cookie rewriting still behaves as expected.

• enhancementEnvoy v1.34.14 is bundled — no separate action needed

  The Envoy bump is included in the Contour image. If you run a managed Envoy deployment alongside Contour, verify your Envoy image is also updated to v1.34.14 to stay consistent with Contour's tested configuration.

Contour v1.31.6 patches a Lua code injection vulnerability (CVE-2026-41246) in Cookie Rewriting that could allow arbitrary code execution in shared Envoy infrastructure.

• securityPatch immediately if you allow untrusted users to create/modify HTTPProxy resources

  CVE-2026-41246 is a privilege escalation path in multi-tenant clusters. Any user with RBAC write access to HTTPProxy objects can inject arbitrary Lua into Envoy — and since Envoy is shared infrastructure, the blast radius extends to other tenants and exposes xDS credentials. Upgrade to v1.31.6 now. If you cannot upgrade immediately, audit existing HTTPProxy objects for suspicious pathRewrite values and tighten RBAC so only trusted principals can write HTTPProxy resources.

• enhancementReview RBAC around HTTPProxy write permissions regardless of upgrade status

  This CVE class — user-controlled values interpolated into code — is a design risk whenever untrusted users can write Kubernetes custom resources that drive proxy configuration. Use this as a prompt to apply least-privilege RBAC on HTTPProxy, HTTPRoute, and similar resources across your clusters. Namespace-scoped RBAC and admission webhooks that validate pathRewrite values are good mitigations to layer on top of the patch.

Cilium v1.19.3 is a dense bugfix release targeting memory leaks, panics, and networking correctness issues — particularly in DSR mode, WireGuard dual-stack, and IPAM edge cases.

• securityUpdate go-jose dependency (CVE exposure)

  go-jose/go-jose was bumped to v4.1.4 as a security update. While Cilium's direct exposure depends on usage paths, this library is involved in JWT/token handling. If you're running automated audits or supply chain checks, note this dependency version change in your SBOM.

• breakingIPAM corruption risk on dual-stack clusters — upgrade urgently

  A bug in dual-stack cluster-pool IPAM could cause IPv4 PodCIDRs to be freed and reassigned after an operator restart if duplicate IPv6 PodCIDRs existed. This is a data-plane correctness issue that causes silent IP conflicts between nodes. If you run dual-stack with cluster-pool IPAM, upgrade to v1.19.3 before your next operator restart. After upgrading, inspect node CIDRs for any anomalies.

• enhancementMemory leak fixes matter more than they look — plan your upgrade

  Two distinct memory leaks are patched here. One is triggered by incremental policy updates (common in dynamic environments), the other by policy create/delete cycles. In clusters with frequent NetworkPolicy churn — CI namespaces, multi-tenant platforms, or GitOps-driven policy — these leaks can accumulate over hours or days. If your Cilium agents show gradual memory growth, this release likely explains it. Rolling restart after upgrade is sufficient; no config changes needed.

Cilium v1.18.9 is a patch release focused on memory leak fixes, panic prevention, and load balancer correctness — several bugs here could cause real production incidents.

• securitygo-jose dependency patched — update if using Cilium's auth features

  go-jose/go-jose/v4 was updated to v4.1.4 as a security fix. If your Cilium deployment uses mutual auth or any JWT/JOSE-based features, this patch addresses a known vulnerability in that library. Treat this upgrade as a priority if those code paths are active.

• breakingIPAM reassignment risk: upgrade dual-stack clusters promptly

  If you run dual-stack with cluster-pool IPAM, a bug could reassign a node's IPv4 PodCIDR to another node after an operator restart — with an existing duplicate IPv6 PodCIDR in play. This causes IP conflicts and broken pod networking. Upgrade to 1.18.9 before your next operator restart or planned maintenance window.

• enhancementMemory leaks under policy churn are fixed — relevant for dynamic environments

  Two separate memory leak paths were closed: one from incremental policy updates, one from policies being frequently created and deleted. Clusters with high policy churn (CI environments, multi-tenant setups, frequent namespace deployments) were slowly leaking memory. After upgrading, monitor Cilium agent memory baselines — you should see stabilization over hours to days.

edge-26.4.3 adds per-pod proxy env var injection via annotation, bumps proxy to v2.349.0, and validates Kubernetes 1.35 compatibility across policy tests.

• securityrustls-webpki patch — verify if you vendor Rust dependencies

  rustls-webpki was bumped to 0.103.11. This library is part of Linkerd's mTLS stack. No CVE is listed, but if your organization audits or vendors Rust dependencies, update your lockfiles and re-run your SBOM scans to stay current.

• enhancementUse proxy-additional-env to inject custom env vars without custom images

  The new `proxy-additional-env` annotation lets you set environment variables on injected proxies at the pod or namespace scope. This is useful for tuning proxy behavior (e.g., log levels, feature flags) in specific workloads without modifying global Helm values or building custom proxy images. Start using it on non-critical workloads first to validate behavior before rolling out broadly.

• enhancementPlan for Kubernetes 1.35 if you're on the upgrade path

  Linkerd's test suite now covers k8s 1.35, including policy tests. If your team is evaluating or scheduling a cluster upgrade to 1.35, this edge release gives you reasonable confidence that core Linkerd functionality and policy enforcement will hold. Run your own smoke tests against a 1.35 staging cluster before committing to a production upgrade.

v2.12.7 is a targeted bug-fix release addressing ACL bypass vulnerabilities, multiple leafnode panics, a JetStream consumer stuck state, and an MQTT JWT regression from 2.12.6.

• securityPatch ACL bypass bugs immediately if you use deny rules or queue groups

  Two ACL enforcement bugs are fixed here. Overlapping wildcard patterns in deny ACLs were not enforced correctly, and queue subscriptions could bypass non-queue deny rules entirely. If your security model relies on deny-based ACLs — especially with wildcards or mixed queue/non-queue subscribers — treat this as a must-upgrade. Audit your ACL configurations after upgrading to confirm expected deny behavior is active.

• breakingMQTT users on 2.12.6 must upgrade — auth callout JWT was broken

  If you deployed 2.12.6 with MQTT clients using auth callout, JWTs were not being forwarded to the callout service, meaning your auth logic was silently bypassed or failing. This regression is fixed in 2.12.7. Upgrade immediately and verify MQTT client authentication is functioning end-to-end.

• enhancementmax_mem_store and max_file_store can now be increased via config reload

  You can now raise JetStream storage limits without restarting the server — just update the config and reload. Decreasing is still not supported via reload. Useful for capacity adjustments during peak periods without downtime. Plan your storage sizing with headroom so you can expand reactively if needed.