# CVE-2026-88009

## Summary

- **CVE ID:** CVE-2026-88009
- **Severity:** HIGH
- **CVSS Score:** 8.8 (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)
- **CWE:** CWE-444, CWE-1286
- **Published:** Sep 10, 2026
- **Last Modified:** Sep 10, 2026

## 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.

## Affected Products

- traefik — traefik (< 2.11.57)
- traefik — traefik (>= 3.0.0, < 3.7.13)

## References

- [CNA](https://github.com/traefik/traefik/security/advisories/GHSA-f52w-8j3h-j724)
- [CNA](https://github.com/traefik/traefik/pull/13796)
- [CNA](https://github.com/traefik/traefik/commit/58d1e9ca204526823211e30fd4634101c59d58e9)
- [CNA](https://github.com/traefik/traefik/releases/tag/v2.11.57)
- [CNA](https://github.com/traefik/traefik/releases/tag/v3.7.13)

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._