Vulnerability Description
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/basic_auth.go deduplicates concurrent password checks with a singleflight key built from the delimiter-free concatenation of password and secret, allowing an attacker who has a valid credential and the stored hash to authenticate as an unconfigured username when headerField trusts the forwarded identity. This issue is fixed in 3.6.25 and 3.7.10.
Related Weaknesses (CWE)
References
- https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e3
- https://github.com/traefik/traefik/pull/13572
- https://github.com/traefik/traefik/releases/tag/v3.6.25
- https://github.com/traefik/traefik/releases/tag/v3.7.10
- https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf
FAQ
What is CVE-2026-71326?
CVE-2026-71326 is a documented vulnerability. 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/basic_auth.go deduplicates concurrent passwo...
How severe is CVE-2026-71326?
CVSS scoring is not yet available for CVE-2026-71326. Check NVD for updates.
Is there a patch for CVE-2026-71326?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.