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.

Attack Vector Network

Attack Complexity Low

Privileges Required High

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
traefik traefik affected
Version Status Constraints
>= 3.6.11, < 3.6.25 affected —
>= 3.7.0, < 3.7.10 affected —

No data.

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-6765-c87h-8mrf Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350 cve-icon
https://github.com/traefik/traefik/pull/13572 cve-icon
https://github.com/traefik/traefik/releases/tag/v3.6.25 cve-icon
https://github.com/traefik/traefik/releases/tag/v3.7.10 cve-icon
https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf cve-icon
History

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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-06T16:34:23.931Z

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

Link: CVE-2026-71326

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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

Weaknesses