CVE-2026-54763
Reported by GitHub_M · Published July 6, 2026
Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| traefik | traefik | < 2.11.51, >= 3.0.0-beta1, < 3.6.22, >= 3.7.0-ea.1, < 3.7.6 |
| github.com | traefik/traefik/v3 | 0, 3.7.0, 0 |
| github.com | traefik/traefik/v2 | 0, 0, 0 |
| alpine | traefik | 0, 0, 0 |
| traefik | traefik | < 2.11.51, >= 3.0.0-beta1, < v3.6.22, >= 3.7.0-ea.1, < v3.7.6 |
Timeline
- Jul 6, 2026 CVE Published
- Jul 7, 2026 EPSS Score
- Jul 7, 2026 Coalition ESS Score
- Jul 9, 2026 Security Advisory
- Aug 7, 2026 EPSS Score
References
- https://github.com/traefik/traefik/security/advisories/GHSA-x677-9fxg-v5c5 x_refsource_CONFIRM
- https://github.com/traefik/traefik/pull/13262 x_refsource_MISC
- https://github.com/traefik/traefik/commit/108a5264473a2cbc8f12d6d691a3c6553cdf2c1b x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-54763 advisory
- https://github.com/advisories/GHSA-x677-9fxg-v5c5 advisory
- https://github.com/traefik/traefik/releases/tag/v2.11.51 url
- https://github.com/traefik/traefik/releases/tag/v3.6.22 url
- https://github.com/traefik/traefik/releases/tag/v3.7.6 url