Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Traefik | Traefik | < 3.6.21 |
Related Weaknesses (CWE)
References
- https://github.com/traefik/traefik/releases/tag/v3.6.21Release NotesPatch
- https://github.com/traefik/traefik/releases/tag/v3.7.5Release NotesPatch
- https://github.com/traefik/traefik/security/advisories/GHSA-3g6v-2r68-prfcExploitMitigationPatch
FAQ
What is CVE-2026-54761?
CVE-2026-54761 is a vulnerability with a CVSS score of 7.1 (HIGH). 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 all...
How severe is CVE-2026-54761?
CVE-2026-54761 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-54761?
Check the references section above for vendor advisories and patch information. Affected products include: Traefik Traefik.