Traefik up to 2.11.50/3.6.21/3.7.5 BasicAuth/DigestAuth/ForwardAuth improper authorization

Summaryinfo

A vulnerability described as critical has been identified in Traefik up to 2.11.50/3.6.21/3.7.5. Affected by this issue is some unknown functionality of the component BasicAuth/DigestAuth/ForwardAuth. The manipulation results in improper authorization. This vulnerability is reported as CVE-2026-54763. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability classified as critical has been found in Traefik up to 2.11.50/3.6.21/3.7.5. Affected is an unknown code block of the component BasicAuth/DigestAuth/ForwardAuth. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-54763 since 06/16/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1548.002 by the MITRE ATT&CK project.

Upgrading to version 2.11.51, 3.6.22 or 3.7.6 eliminates this vulnerability.

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Productinfo

Name

• Traefik

Version

• 2.11.0
• 2.11.1
• 2.11.2
• 2.11.3
• 2.11.4
• 2.11.5
• 2.11.6
• 2.11.7
• 2.11.8
• 2.11.9
• 2.11.10
• 2.11.11
• 2.11.12
• 2.11.13
• 2.11.14
• 2.11.15
• 2.11.16
• 2.11.17
• 2.11.18
• 2.11.19
• 2.11.20
• 2.11.21
• 2.11.22
• 2.11.23
• 2.11.24
• 2.11.25
• 2.11.26
• 2.11.27
• 2.11.28
• 2.11.29
• 2.11.30
• 2.11.31
• 2.11.32
• 2.11.33
• 2.11.34
• 2.11.35
• 2.11.36
• 2.11.37
• 2.11.38
• 2.11.39
• 2.11.40
• 2.11.41
• 2.11.42
• 2.11.43
• 2.11.44
• 2.11.45
• 2.11.46
• 2.11.47
• 2.11.48
• 2.11.49
• 2.11.50
• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3
• 3.6.4
• 3.6.5
• 3.6.6
• 3.6.7
• 3.6.8
• 3.6.9
• 3.6.10
• 3.6.11
• 3.6.12
• 3.6.13
• 3.6.14
• 3.6.15
• 3.6.16
• 3.6.17
• 3.6.18
• 3.6.19
• 3.6.20
• 3.6.21
• 3.7.0
• 3.7.1
• 3.7.2
• 3.7.3
• 3.7.4
• 3.7.5

Website

• Product: https://github.com/traefik/traefik/

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