CVE-2026-54761
HighCVSS 7.1Exploitation Probability (EPSS)
Low risk30th percentile — higher than 30% of all known CVEs
Summary
Vulnerability in Traefik (versions prior to 3.6.21 and 3.7.5) in the Kubernetes Gateway provider affects the crossProviderNamespaces allowlist. For HTTPRoute rules with multiple backendRefs (WRR), Traefik incorrectly evaluates the allowlist against the target backendRef.namespace instead of the route's own namespace. This allows an HTTPRoute from a non-allowlisted namespace to reference internal Traefik services (e.g., api@internal) by pointing backendRef.namespace at an allowlisted namespace covered by a ReferenceGrant.
Risk Assessment
Exploitation exposes internal Traefik services on the data plane, potentially leading to unauthorized access to management interfaces (dashboard, API, REST) and possible proxy takeover.
Recommendation
Immediately update Traefik to version 3.6.21 or 3.7.5. Restrict the ability to create HTTPRoute and ReferenceGrant to trusted users and monitor logs for suspicious routes.
Original NVD description (English source)
Traefik is an HTTP reverse proxy and load balancer. Prior to 3.6.21 and 3.7.5, there is a high severity vulnerability in Traefik's Kubernetes Gateway provider affecting the crossProviderNamespaces allowlist. For HTTPRoute rules that declare multiple (WRR) backendRefs, Traefik evaluates the allowlist against the target backendRef.namespace instead of the route's own namespace. As a result, an HTTPRoute created in a namespace that is not allow-listed can reference a cross-provider TraefikService such as api@internal, dashboard@internal or rest@internal by pointing backendRef.namespace at an allow-listed namespace covered by a Gateway API ReferenceGrant, exposing internal Traefik services on the data plane. Exploitation requires the ability to create an accepted HTTPRoute and a matching ReferenceGrant from an allow-listed namespace; it does not require any change to Traefik static configuration, RBAC, or the deployment itself. This vulnerability is fixed in 3.6.21 and 3.7.5.