Releases

Check if affected (7)

• securityhighCVE-2026-48743, HTTP/3 headers-only content-length validation

  Applies if you enable envoy.reloadable_features.quic_validate_headers_only_content_length.

  CVE-2026-48743 validates content lengths for HTTP/3 headers-only requests and responses and resets the stream when the values are inconsistent. The change is guarded by the runtime flag envoy.reloadable_features.quic_validate_headers_only_content_length.

• securityhighCVE-2026-48042, JSON parser nesting depth limit

  Applies if you set envoy.reloadable_features.limit_json_parser_nesting_depth to false.

  CVE-2026-48042 limits JSON nesting depth to 1000. The limit can be relaxed to 10K by setting envoy.reloadable_features.limit_json_parser_nesting_depth to false.

• securitymediumCVE-2026-47207, ext_proc server response handling

  Applies if you use the ext_proc server.

  CVE-2026-47207 fixes unexpected ProcessingResponses sent by the ext_proc server to Envoy.

• + 4 more on the release page

Check if affected (11)

• securityhighCVE-2026-47220 in the %REQUESTED_SERVER_NAME% formatter

  Applies if you configure the %REQUESTED_SERVER_NAME% formatter.

  CVE-2026-47220 fixes a crash in the %REQUESTED_SERVER_NAME% formatter when the host or original host is not set correctly while the formatter accesses the host value.

• securityhighCVE-2026-48044 in the Zstd decompressor

  Applies if you use the Zstd decompressor.

  CVE-2026-48044 fixes memory exhaustion in the Zstd decompressor. The MaxInflateRatio limit is now enforced inside the inner decompression loop.

• securityhighCVE-2026-48743 HTTP/3 headers-only content-length validation

  Applies if you use HTTP/3 and enable envoy.reloadable_features.quic_validate_headers_only_content_length.

  CVE-2026-48743 fixes HTTP/3 content-length validation for headers-only requests and responses. Inconsistent content lengths now reset the stream, guarded by the runtime flag envoy.reloadable_features.quic_validate_headers_only_content_length.

• + 8 more on the release page

Check if affected (5)

• securityhighCVE-2026-48743 HTTP/3 content-length validation

  Applies if you use HTTP/3.

  The Envoy security update fixes HTTP/3 headers-only request and response content-length validation, including the envoy.reloadable_features.quic_validate_headers_only_content_length feature.

• securitymediumCVE-2026-47207 ext_proc response handling

  Applies if you use the ext_proc extension.

  The Envoy security update fixes a bug where the ext_proc server sends unexpected ProcessingResponses to Envoy.

• securitymediumCVE-2026-47221 HTTP 303 redirect handling

  Applicability is not stated in the release notes.

  The Envoy security update fixes an issue when handling HTTP 303 internal redirects.

• + 2 more on the release page

Check if affected (1)

• breakingPILOT_ENABLE_ALPHA_GATEWAY_API guard removed from ListenerSet

  Applies if you use the ListenerSet API.

  The ListenerSet feature is no longer guarded by the PILOT_ENABLE_ALPHA_GATEWAY_API feature flag because it is no longer experimental in Gateway API v1.5.0.

Check if affected (1)

• breakingAuthentication required for XDS debug endpoints

  Applies if ENABLE_DEBUG_ENDPOINT_AUTH is set.

  The XDS debug endpoints, syncz and config_dump, on port 15010 now require authentication when ENABLE_DEBUG_ENDPOINT_AUTH=true, which is the default.

Check if affected (2)

• securityRegex handling in AuthorizationPolicy identity fields

  Applicability is not stated in the release notes.

  AuthorizationPolicy no longer embeds unescaped regex metacharacters from certain identity fields in the generated Envoy SafeRegex. This fixes the resulting authorization bypass.

• breakingThe AMBIENT_ENABLE_AWS_BRANCH_ENI_PROBE setting and kubelet health probes

  Applies when ambient mesh pods run on AWS EKS and use Security Groups for Pods (branch ENI).

  istio-cni fixes kubelet health probe failures for ambient mesh pods on AWS EKS when using Security Groups for Pods (branch ENI). The fix covers the AMBIENT_ENABLE_AWS_BRANCH_ENI_PROBE capability.

Check if affected (1)

• securityEscaped regex metacharacters in AuthorizationPolicy identity fields

  Applies if you configure source.principals or source.namespaces.

  AuthorizationPolicy now escapes regex metacharacters in identity fields before embedding them in generated Envoy SafeRegex expressions. This prevents characters such as . or [ in legal Kubernetes names from being treated as regex wildcards in source.principals suffix matches and source.namespaces.

Check if affected (10)

• securityhighCVE-2026-26308 multivalue header bypass fix

  Applies if you use RBAC.

  CVE-2026-26308 fixes a multivalue header bypass in RBAC.

• securityhighCVE-2026-31837 and GHSA-v75c-crr9-733c JWKS resolver authentication fix

  Applies if you use JWKS Resolver.

  CVE-2026-31837 and GHSA-v75c-crr9-733c fix the JWKS Resolver failure that could allow authentication bypass using known default keys.

• securitymediumCVE-2026-26311 HTTP decode method restriction

  Applies if you use HTTP.

  CVE-2026-26311 blocks HTTP decode methods after a downstream reset.

• + 7 more on the release page

Check if affected (3)

• securityAuthentication for XDS debug endpoints on port 15010

  Applies if you expose XDS debug endpoints.

  XDS debug endpoints on plaintext port 15010 now require authentication, preventing unauthenticated access to proxy configuration.

• securityBearer token realm URL validation for WasmPlugin image fetching

  Applies if you use WasmPlugin image fetching.

  WasmPlugin image fetching now validates bearer token realm URLs to fix a potential SSRF.

• securityNamespace-based authorization for HTTP debug endpoints on port 15014

  Applies if you expose HTTP debug endpoints.

  HTTP debug endpoints on port 15014 now enforce namespace-based authorization, preventing cross-namespace proxy data access.

Check if affected (6)

• securityhighCVE-2026-26308 multivalue header bypass fix

  Applies if you use RBAC.

  CVE-2026-26308 fixes a multivalue header bypass in RBAC.

• securityhighCVE-2026-31837 and GHSA-v75c-crr9-733c JWKS Resolver authentication fix

  Applies if you use JWKS Resolver.

  CVE-2026-31837 and GHSA-v75c-crr9-733c fix a JWKS Resolver failure that could allow authentication bypass using known default keys.

• securitymediumCVE-2026-31838 and GHSA-974c-2wxh-g4ww debug endpoint access fix

  Applies if you use Debug Endpoints.

  CVE-2026-31838 and GHSA-974c-2wxh-g4ww address cross-namespace proxy data access through debug endpoints.

• + 3 more on the release page

Check if affected (4)

• securitycriticalCVE-2025-68121 TLS session resumption validation

  Applies if you use Config.Clone with mutations or Config.GetConfigForClient.

  This release fixes crypto/tls session resumption when ClientCAs or RootCAs change between the initial and resumed handshake. The fix covers configurations using Config.Clone with mutations or Config.GetConfigForClient.

• securityGateway deployment controller resource validation

  Applies if the gateway deployment controller runs.

  This release adds safeguards to the gateway deployment controller that validate object types, names, and namespaces before creating Kubernetes resources. The validation prevents arbitrary resource creation through template injection.

• securityResource annotation validation against container injection

  Applies if you configure resource annotations.

  This release updates resource annotation validation to reject newlines and control characters. The change prevents template rendering from injecting containers into pod specifications.

• + 1 more on the release page

Check if affected (4)

• breakingDefault iptables reconciliation

  Applies when the istio-cni DaemonSet is upgraded.

  iptables reconciliation is enabled by default. It updates network rules automatically when the istio-cni DaemonSet is upgraded.

• breakingDefault debug endpoint authorization

  Applies to debug endpoints on port 15014.

  Debug endpoint authorization is enabled by default for debug endpoints on port 15014. It provides namespace-based access controls.

• breakingDefault HTTP compression for Envoy metrics

  Applies to Envoy metrics at the Prometheus stats endpoint based on client Accept-Header values.

  HTTP compression for Envoy metrics is enabled by default at the Prometheus stats endpoint. Compression uses brotli, gzip, or zstd based on client Accept-Header values.

• + 1 more on the release page

Check if affected (2)

• securityGateway deployment controller resource validation

  Applies if the gateway deployment controller runs.

  The gateway deployment controller now validates object types, names, and namespaces before creating Kubernetes resources through template rendering. This prevents arbitrary resource creation through template injection.

• breakingNamespace-based authorization for debug endpoints

  Applies if you use debug endpoints on port 15014.

  Namespace-based authorization now restricts non-system access on port 15014 to the config_dump, ndsz, and edsz endpoints and to same-namespace proxies. Compatibility behavior can be disabled with ENABLE_DEBUG_ENDPOINT_AUTH=false.