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VulnerabilityPublished Updated

github.com/traefik/traefik/v2 · V2: Duplicate Advisory: Traefik: Authentication Bypass via Path Traversal in ReplacePathRegex Middleware

Affects github.com/traefik/traefik/v2Source GCVE Database

0

CVSS 7.8 High · fixed in 2.11.52 : patch github.com/traefik/traefik/v2 soon.

Data as of 6 Aug 2026, 18:24 UTC

CVSS 4.0 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 2.11.52
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/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

What to do

Affected software

ProductAffectedFixed in
Gogithub.com/traefik/traefik/v2Affected
  • <=2.11.51
Fixed in–

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AI-suggested

Upgrade Traefik to version 2.11.52, 3.6.23, or 3.7.7 or later where this vulnerability is fixed. Until patched, avoid using ReplacePathRegex middleware configurations that capture user-controlled path segments without mandatory path separators. Patch status is confirmed by the vendor advisory.

Description

## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-cxjq-mrr5-89rv. This link is maintained to preserve external references. ## Original Description Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex "^/api(.*)", replacement "/$1"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a backend that normalizes paths resolves to a protected route, bypassing authentication middleware. Fixed in v2.11.52, v3.6.23, and v3.7.7.

References

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