Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing

Summary There is a low severity vulnerability in Traefik's BasicAuth middleware. Concurrent password verifications are deduplicated through a singleflight group whose key was the delimiter-free concatenation of the submitted password and the stored secret, so a request carrying an unconfigured...

CVE-2026-71326

CVE-2026-71326 affects Traefik’s BasicAuth middleware (pkg/middlewares/auth/basic_auth.go) in 3.6.11–3.6.25 and 3.7.10. The vulnerability arises from deduplicating concurrent password checks using a singleflight key built from the delimiter-free concatenation of password and secret, enabling an a...

EUVD-2026-54297

Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.6.25 and 3.7.10, Traefik's BasicAuth middleware in pkg/middlewares/auth/basicauth.go deduplicates concurrent password checks with a singleflight key built from the delimiter-free concatenation of password and...