Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass
Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. Prior to 1.7.4 and 1.8.1, an HTTPRoute can use an extension-managed custom backendRef to reference a backend resource in another namespace without a matching Gateway API ReferenceGrant in the target namespace. The custom-backend branch in internal/gatewayapi/route.go omits validateBackendNamespace, allowing the route-owning namespace to bind to and use the resource without the backend namespace owner's consent and violating the Gateway API cross-namespace authorization model. This issue is fixed in versions 1.7.4 and 1.8.1.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-53718US | —OT elevated | — | ||
Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. Prior to 1.7.4 and 1.8.1, an HTTPRoute can use an extensio… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/envoyproxy/gateway/commit/5a78db82b7cf4fc5bebbeda2c50952892038a464WEB
- https://github.com/envoyproxy/gateway/commit/96e2b750868a459ace4b8b68e6a6e4fb0152b9b7WEB
- https://github.com/envoyproxy/gateway/commit/b4737180c7e597490c6363075c565fa8cf24eeadWEB
- https://github.com/envoyproxy/gateway/pull/9171WEB
- https://github.com/envoyproxy/gateway/pull/9172WEB
- https://github.com/envoyproxy/gateway/pull/9173WEB
- https://github.com/envoyproxy/gateway/releases/tag/v1.7.4WEB
- https://github.com/envoyproxy/gateway/releases/tag/v1.8.1WEB
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