ISTIO-SECURITY-2026-007

CVE

Envoy CVEs

• GHSA-8vc2-jrm4-835w: (CVSS score 7.5): Fixed an unauthenticated remote crash (null pointer dereference) in the OAuth2 HTTP filter when handling a CONNECT request without a :path header.
• GHSA-47vj-9r25-wv5j: (CVSS score 6.5): Fixed a crash in the api_key_auth HTTP filter when hiding credentials on a CONNECT request without a :path header.

Istio CVEs

• GHSA-w44g-8m76-8gc5 (CVSS score 7.4, High): AuthorizationPolicy method rules are bypassed over HTTP/2 by changing the case of the method. Credit: This vulnerability was discovered and reported by izzy0101010101.
• GHSA-7p2q-4xvg-vxc6 (CVSS score 7.7, High): istiod crashes (denial of service) in ambient mode when a ServiceEntry or other service claims the address of an IP-addressed waypoint. Credit: This vulnerability was discovered and reported by yshch.

AuthorizationPolicy method rules bypassed over HTTP/2

An AuthorizationPolicy DENY rule with methods (or an ALLOW rule with notMethods) was compiled to a case-sensitive :method matcher. Over HTTP/2, a request whose method differs only in case (for example post instead of POST) did not match the rule and was forwarded to the workload, bypassing the policy. HTTP/1.1 is not affected because the codec rejects non-uppercase methods before authorization. Method matching is now case-insensitive.

istiod denial of service via waypoint address collision

In ambient mode, istiod resolves the service that owns an IP-addressed waypoint by network and IP address only. When a second service, such as a ServiceEntry in any namespace, claimed the same address, istiod panicked and crash-looped until the colliding resource was removed. A user allowed to create ServiceEntry resources in their own namespace could stop configuration distribution and certificate rotation for the whole mesh. Colliding addresses are now skipped with a warning.

Am I Impacted?

• Envoy CVEs: You are potentially impacted if you run an affected Istio release and use the OAuth2 or api_key_auth HTTP filters.

• AuthorizationPolicy method bypass: You are impacted if you use AuthorizationPolicy DENY rules with methods, or ALLOW rules with notMethods, and clients can reach the workload over HTTP/2. Policies that only use ALLOW rules with an explicit methods list are not affected.

• istiod denial of service: You are impacted if you run ambient mode with an IP-addressed waypoint (for example a waypoint Gateway annotated with networking.istio.io/address-type: IPAddress) and users other than mesh administrators can create ServiceEntry resources. Waypoints that report a hostname, which is the default, are not affected.

Mitigation

• For Istio 1.31 users: upgrade to 1.31.2 or later.
• For Istio 1.30 users: upgrade to 1.30.6 or later.
• For Istio 1.29 users: upgrade to 1.29.9. This is the final 1.29 release, as 1.29 reached end of life on October 15, 2026. Plan an upgrade to 1.30 or later.
• As an interim measure for the AuthorizationPolicy bypass, use ALLOW policies with an explicit methods allow-list instead of DENY or notMethods rules.
• As an interim measure for the istiod denial of service, restrict ServiceEntry create and update permissions to trusted administrators using Kubernetes RBAC, or use hostname-addressed waypoints.

Other Istio Security Fixes

This release also includes the following security fixes that were not assigned CVEs. See the release notes for each version for details.

• istioctl now verifies the istiod certificate when connecting to XDS with a service account token. Credit: This issue was reported by Leon Zlobecki.
• istioctl manifest translate now escapes values written into generated install shell scripts. Credit: This vulnerability was discovered and reported by OpenSec Intelligence.
• Fixed an istiod panic when the OIDC/JWT authenticator received a token with a malformed sub claim. Credit: This issue was reported by Kaizhe Huang.
• Hardened the experimental Kubernetes CSR RA path (EXTERNAL_CA=ISTIOD_RA_KUBERNETES_API): opaque errors to callers, a bounded watch loop, and a new MAX_RA_WORKLOAD_CERT_TTL cap. Credit: This issue was reported by Juno Im.
• The Wasm OCI image fetcher no longer falls back to plaintext HTTP for registries that are not listed in WASM_INSECURE_REGISTRIES. Credit: This vulnerability was discovered and reported by Adam Korczynski.
• istiod debug endpoints now require an exact proxyID match. Credit: This issue was reported by 박현범.
• Added PILOT_ENABLE_STRICT_GATEWAY_MERGING to 1.29 and 1.30 to prevent cross-namespace merging of Istio Gateway resources with managed Gateway API gateways. It is disabled by default in 1.29 and 1.30 and enabled by default starting in 1.31.