CVE-2026-71326
Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing
- State
- Published
- Severity
- 2.1 Low
- Published
- Aug 6, 2026
- Updated
- Aug 8, 2026
- Reserved
- Aug 5, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 2.1 Low | CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
traefiktraefik |
|
References
- https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf
- https://github.com/traefik/traefik/pull/13572
- https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350
- https://github.com/traefik/traefik/releases/tag/v3.6.25
- https://github.com/traefik/traefik/releases/tag/v3.7.10
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