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.
History

Sat, 08 Aug 2026 03:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 07 Aug 2026 02:45:00 +0000

Type Values Removed Values Added
First Time appeared Traefik
Traefik traefik
Vendors & Products Traefik
Traefik traefik

Thu, 06 Aug 2026 22:15:00 +0000

Type Values Removed Values Added
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.
Title Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing
Weaknesses CWE-287
References
Metrics cvssV4_0

{'score': 2.1, 'vector': '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-08T02:12:44.764Z

Reserved: 2026-08-05T18:14:42.065Z

Link: CVE-2026-71326

cve-icon Vulnrichment

Updated: 2026-08-08T02:12:39.846Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-07T02:30:05Z