Envoy Gateway's xDS gRPC server, when configured in GatewayNamespaceMode, installs a JWT StreamInterceptor but omits a UnaryInterceptor, leaving unary Fetch RPCs unauthenticated. Additionally, the streaming interceptor only authenticates discoveryv3.DeltaDiscoveryRequest messages, while discoveryv3.DiscoveryRequest messages used by the State-of-the-World protocol bypass JWT validation due to a failed type assertion. This flaw permits any pod with network access to port 18000 to retrieve highly sensitive data such as TLS private keys, all xDS resources, backend endpoints, and routing configurations without authentication. The vulnerability is addressed in Envoy Gateway versions 1.7.4 and 1.8.1.

An attacker with network access to port 18000 on the Envoy Gateway can exploit this vulnerability to retrieve TLS private keys, all xDS resources, backend endpoints, and routing configuration without authentication. This compromises confidentiality of critical security assets and could lead to further attacks leveraging the exposed sensitive information. The CVSS 3.1 score is 7.4 (High), reflecting the significant confidentiality impact with no required privileges or user interaction.

Upgrade Envoy Gateway to version 1.7.4 or later, or 1.8.1 or later, where this vulnerability is fixed. No other mitigations are specified. Patch status is confirmed fixed in these versions.