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Istio

1.31.2Networking & Messaging
Oct 16, 2026

ACTION 3CHECK 7PLAN 1OTHER 17

A security-focused maintenance release with vulnerability fixes and correctness repairs. It also adds connection and routing controls and changes several operator-visible defaults and constraints.

Action needed (3)

  • securityMAX_RA_WORKLOAD_CERT_TTL workload certificate TTL cap

    The new MAX_RA_WORKLOAD_CERT_TTL environment variable caps the workload certificate TTL at a default of 48h. This constraint limits the certificate lifetime configured through the RA settings, including MAX_WORKLOAD_CERT_TTL and EXTERNAL_CA=ISTIOD_RA_KUBERNETES_API.

  • securityistiod debug endpoint proxyID matching

    istiod debug endpoints, including /debug/config_dump, /debug/edsz, and the XDS istio.io/debug/config_dump type, no longer match proxyID as a substring. The fix ships in istiod debug endpoint matching.

  • breakingClient-side request timeout behavior

    Requests now time out on the client side, so a stuck request is canceled and the component can recover on its own. The behavior is associated with ISTIO_KUBE_HEADER_TIMEOUT, ISTIO_KUBE_REQUEST_TIMEOUT, and the kube_client_deadline_fired_total metric.

Check if affected (7)

  • securityGHSA-8vc2-jrm4-835w OAuth2 HTTP filter crash fix

    Applies if you use the OAuth2 HTTP filter.

    GHSA-8vc2-jrm4-835w fixes an unauthenticated remote crash in the OAuth2 HTTP filter when a CONNECT request lacks a :path header. The fix ships in the OAuth2 HTTP filter.

  • securityGHSA-47vj-9r25-wv5j API key authentication filter crash fix

    Applies if you use the api_key_auth HTTP filter.

    GHSA-47vj-9r25-wv5j fixes a crash in the api_key_auth HTTP filter when a CONNECT request lacks a :path header. The fix ships in the api_key_auth HTTP filter.

  • securityGHSA-w44g-8m76-8gc5 AuthorizationPolicy method-rule enforcement

    Applicability is not stated in the release notes.

    GHSA-w44g-8m76-8gc5 fixes an AuthorizationPolicy bypass over HTTP/2 when the request method case is changed. The correction applies to AuthorizationPolicy method rules.

  • securityGHSA-7p2q-4xvg-vxc6 ambient-mode istiod crash fix

    Applicability is not stated in the release notes.

    GHSA-7p2q-4xvg-vxc6 fixes an istiod crash in ambient mode when a ServiceEntry or another service claims the address of an IP-addressed waypoint. The fix ships in istiod.

  • securityistioctl script command-injection fix

    Applicability is not stated in the release notes.

    istioctl no longer permits crafted values to inject additional shell commands when generated scripts are run. The correction ships in istioctl script handling.

  • securityCreateCertificate Kubernetes CSR RA error handling

    Applies if you configure EXTERNAL_CA=ISTIOD_RA_KUBERNETES_API.

    CreateCertificate no longer returns raw Kubernetes API error text to callers on the experimental Kubernetes CSR RA path. The correction applies to the EXTERNAL_CA=ISTIOD_RA_KUBERNETES_API configuration.

  • securityWASM_INSECURE_REGISTRIES plaintext retry restriction

    Applies if you configure WASM_INSECURE_REGISTRIES.

    Plaintext retries now occur only for registries explicitly allowlisted through WASM_INSECURE_REGISTRIES. The restriction ships in WASM image registry retry handling.

Plan ahead (1)

  • deprecatedThe overload.global_downstream_max_connections runtime flag, deprecated

    Applies if you configure overload.global_downstream_max_connections.

    The overload.global_downstream_max_connections runtime flag is deprecated. The deprecation applies to this runtime configuration flag.

All 17 other recorded changesfixes 12 · additions 4 · value changes 1

fixes (12)

  • Fixed a panic in istiod when the OIDC/JWT authenticator received a token with a malformed sub claim.
  • Fixed the Kubernetes CSR watch loop using an abandoned time.After timer that could leave a goroutine running past request completion
  • Fixed an HTTPRoute rule with several InferencePool backendRefs configuring only one endpoint picker.
  • Fixed two HTTPRoute s sharing a rules[].name on the same gateway overwriting each other’s endpoint picker.
  • Fixed a route rule losing its InferencePool endpoint picker when it also carried a CORS filter.
  • Fixed sidecar proxy UID/GID resolution on OpenShift for workloads bound to a custom SecurityContextConstraint
  • Fixed an issue where, with PILOT_FILTER_GATEWAY_CLUSTER_CONFIG enabled, incremental CDS pushes removed gateway clusters
  • Fixed an issue where the pre-marshaled workload used for change detection and versioning in ambient was not stable when a workload had more than one service
  • Fixed an issue where the network gateway selected for a workload was picked in a random order when a network had more than one gateway entry
  • Fixed configuration dependency filtering for gateways to exclude unrelated configuration updates.
  • Fixed removing a single event handler from a CRD-backed informer removing every handler on that informer.
  • Fixed an issue where EDS-irrelevant configuration updates coalesced with an endpoint update caused full EDS generation instead of updating only the affected endpoint assignments.

additions (4)

  • Added support for cluster-level connection buffer limits ( clusterPerConnectionBufferLimitBytes ) via connectionSettings in ProxyConfig
  • Added support for globalDownstreamConnectionLimit in ProxyConfig.connectionSettings , providing a first-class API field for configuring the global downstream connection limit.
  • Added a validation warning for ServiceEntry addresses that are catch-all ( 0.0.0.0 , :: ), have an unspecified network ( 0.0.0.0/N , ::/N ), or are a CIDR with a prefix shorter than /8 .
  • by adding the PILOT_ENABLE_WDS_DEBOUNCE environment variable, enabled by default.

value changes (1)

  • aws-lc-rs is updated to 1.18.2, which retries the read instead of aborting.
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