CVE-2026-88009

high

Description

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.57, and 3.7.13, Traefik accepts a rootless HTTP/1 request target that Go stores in URL.Opaque while leaving URL.Path empty. The rewriteRequestBuilder path evaluates routing, path sanitization, forwardAuth, encodedCharacters, and access logging against a path normalized to / but forwards URL.Opaque verbatim to the backend, allowing cross-vhost routing bypass, path-scoped authorization bypass, and access-log evasion when the backend interprets the opaque target as a path. This issue is fixed in 2.11.57 and 3.7.13.

References

https://github.com/traefik/traefik/security/advisories/GHSA-f52w-8j3h-j724

https://github.com/traefik/traefik/releases/tag/v3.7.13

https://github.com/traefik/traefik/releases/tag/v2.11.57

https://github.com/traefik/traefik/pull/13796

https://github.com/traefik/traefik/commit/58d1e9ca204526823211e30fd4634101c59d58e9

Details

Source: Mitre, NVD

Published: 2026-09-10

Updated: 2026-09-10

Risk Information

CVSS v2

Base Score: 6.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 5.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Severity: Medium

CVSS v4

Base Score: 8.8

Vector: 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

Severity: High

EPSS

EPSS: 0.00335