Incorrect Implementation of Authentication Algorithm in Traefik - #VU144550
Published: August 21, 2026
Vulnerability identifier: #VU144550
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-303
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass authentication.
The vulnerability exists due to improper authentication in the digestAuth middleware when handling digest authentication requests for usernames absent from the configured user list. A remote attacker can send a specially crafted authorization header to bypass authentication.
If headerField is configured, the attacker\'s chosen username is forwarded to the backend in the configured request header. The forged username may also be recorded in access logs as the authenticated user.
Affected software
Traefik
Remediation
Install security update from vendor's website.
Traefik - addressed in versions 2.11.55, 3.7.11