Incorrect authorization in Traefik - CVE-2026-48020
Published: July 3, 2026
Vulnerability identifier: #VU136870
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:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-48020
CWE-ID: CWE-863
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass route-level authentication and authorization and access protected backend paths.
The vulnerability exists due to incorrect authorization in the StripPrefix middleware when processing request paths containing .. or percent-encoded %2e%2e with PathPrefix-based public routes. A remote attacker can send a specially crafted request to bypass route-level authentication and authorization and access protected backend paths.
Exploitation requires a configuration where a public router uses PathPrefix together with StripPrefix and a separate router protects backend paths such as admin or internal endpoints.
Affected software
Traefik
How to mitigate CVE-2026-48020
Install security update from vendor's website.
Traefik - addressed in versions 2.11.48, 3.6.19, 3.7.3