Releases

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.

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.

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.

Cilium v1.19.2 is a patch release focused on stability: fixes span IPSec key rotation races, L7 LB policy bypass, clustermesh goroutine leaks, and a world-accessible Envoy admin socket.

• securityPatch the world-accessible Envoy admin socket immediately

  The Envoy admin socket was being created accessible to all users on the node (world-accessible). Any workload on the same node could interact with the Envoy admin API. If you're running Cilium with L7 policies or Envoy-based features, upgrade to v1.19.2 now. No config change needed — the fix is in the binary.

• securityIPSec users: silent packet drops during key rotation are fixed

  A race condition in IPSec key rotation caused packets to be dropped when a peer started using the new key before local XFRM states were ready. If you use IPSec encryption and do rolling key rotations, you were likely seeing unexplained connectivity blips. Upgrade and review your key rotation procedures — the fix also adds logging to the rotation flow, so you'll have better visibility going forward.

• breakingL7 LB ingress policy bypass — check your enforcement posture

  A bug allowed traffic to bypass ingress policies for local backends when L7 load balancing was active. If you rely on Cilium network policy enforcement for local service backends with L7 LB enabled, your policies may not have been enforced as expected. After upgrading to v1.19.2, verify that traffic is behaving as your policies intend — this fix restores correct enforcement, which could change observed traffic patterns.

Cilium v1.18.8 is a bug-fix patch with one critical caveat: GKE users must skip it due to a known regression introduced by the XDP jumbo MTU change.

• securityPatch the world-accessible Envoy admin socket immediately

  The Envoy admin socket was being created with world-readable/writable permissions, exposing it to any process on the node. This is fixed in v1.18.8. If you're running Cilium with L7 policy or any Envoy-based features, upgrade promptly. On existing nodes, verify socket permissions at /var/run/cilium/envoy/sockets/ — world access means any container with host path access could interact with the admin API.

• breakingGKE users: do not deploy v1.18.8

  The XDP jumbo MTU support (PR #44499) introduced a regression on GKE. If you're on GKE, skip this version entirely and upgrade to v1.19.2 instead. Running v1.18.8 on GKE risks network disruption. Non-GKE users are not affected by this specific issue.

• enhancementL7 LB policy bypass and FQDN SNI fixes are worth prioritizing

  Two policy-enforcement bugs are fixed here. First, local backends could bypass ingress policies under L7 LB — meaning traffic wasn't being filtered as expected. Second, wildcard FQDN policies weren't propagating correctly to Envoy when SNI-based matching was in use. If your environment uses either L7 load balancing or FQDN network policies with SNI, this release closes real security gaps. Plan the upgrade accordingly.

Cilium v1.17.14 patches a security issue with Envoy's admin socket permissions and two L7 load balancer policy bypass bugs — upgrade if you use L7 LB or Envoy.

• securityPatch the world-accessible Envoy admin socket immediately

  The Envoy admin socket was being created with world-accessible permissions, meaning any process on the node could potentially interact with it. This is a local privilege escalation risk in multi-tenant or shared node environments. Upgrade to v1.17.14 now — there's no workaround short of restricting filesystem access externally. Check if your nodes have been running older versions and audit whether the socket was exploitable in your threat model.

• securityL7 LB was allowing ingress policy bypass for local backends — fix before trusting policy enforcement

  Ingress policies were not being enforced for local backends when L7 load balancing was active. If you rely on network policy to restrict east-west traffic through L7 LB, your policies may not have been effective. After upgrading, verify your ingress policies are behaving as expected, particularly for services with local endpoint backends.

• enhancementBPF filesystem now included in bugtool — use it for faster incident diagnosis

  The bugtool now captures 'find /sys/fs/bpf' output, which is often the first thing you need when diagnosing BPF map or program issues. No action required, but update your runbooks to note that bugtool output from v1.17.14+ will include this data by default, saving manual SSH steps during incidents.