Traefik (pronounced traffic) is an HTTP reverse proxy and load balancer. In versions prior to 2.11.24, 3.3.6, and 3.4.0-rc2. There is a potential vulnerability in Traefik managing the requests using a PathPrefix, Path or PathRegex matcher. When Traefik is configured to route the requests to a backend using a matcher based on the path, if the URL contains a /../ in its path, it’s possible to target a backend, exposed using another router, by-passing the middlewares chain. This issue has been patched in versions 2.11.24, 3.3.6, and 3.4.0-rc2. A workaround involves adding a `PathRegexp` rule to the matcher to prevent matching a route with a `/../` in the path.
Published: 2025-04-21Modified: 2025-11-25
CVSS 3.xCRITICAL 9.1
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NCVSS 4.0HIGH 8.8
CVSS:4.0/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/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X