Use of Incorrectly-Resolved Name or Reference in Traefik - CVE-2026-40912
Published: May 5, 2026
Vulnerability identifier: #VU129678
CSH Severity: High
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-40912
CWE-ID: CWE-706
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Traefik
Traefik
Software vendor:
Containous
Containous
Description
The vulnerability allows a remote attacker to bypass authentication and access protected content.
The vulnerability exists due to use of incorrectly resolved path references in StripPrefixRegex middleware when processing percent-encoded URL paths together with ForwardAuth, BasicAuth, or DigestAuth. A remote attacker can send a specially crafted request with a percent-encoded dot in the prefix portion of the URL to bypass authentication and access protected content.
Exploitation requires a backend that performs dot-segment normalization.
Remediation
Install security update from vendor's website.