CVE-2026-53714

Envoy Gateway versions prior to 1.7.4 and 1.8.1 expose the xDS gRPC server without authentication when deployed in GatewayNamespaceMode (provider.kubernetes.deploy.type=GatewayNamespace): a JWT StreamInterceptor authenticates only discoveryv3.DeltaDiscoveryRequest messages, no UnaryInterceptor is installed at all, and discoveryv3.DiscoveryRequest messages used by the State-of-the-World protocol fail a type assertion and are accepted without JWT validation. As a result, any pod that can reach the gateway's port 18000 can invoke unauthenticated unary Fetch RPCs or the State-of-the-World streaming path. This allows an attacker to retrieve TLS private keys via StreamSecrets, all xDS resources via StreamAggregatedResources, backend endpoints via StreamClusters or StreamEndpoints, and routing configuration via StreamRoutes or StreamListeners. Organizations running affected releases in GatewayNamespaceMode where port 18000 is reachable from other pods in the cluster are impacted. No public proof of concept is known and the issue is not in the CISA KEV catalog.

What to do: Upgrade Envoy Gateway to 1.7.4 or 1.8.1 (or later) as soon as possible. If you run GatewayNamespaceMode, apply Kubernetes NetworkPolicies that restrict access to port 18000 on the gateway pods so only the intended agent/proxy pods can connect. Because StreamSecrets exposes TLS private keys, rotate any certificates served by an affected gateway and audit logs for unexpected unauthenticated Fetch, StreamSecrets, or State-of-the-World DiscoveryRequest calls.