Vulnerability · Published Jul 22, 2026 · Assigned by VulnCheck

CVE-2026-65600Traefik before v2.11.52 Authentication Bypass via ReplacePathRegex

High 7.8

In plain English

A high-severity path traversal in traefik from traefik. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.8High

Exploit odds (30 days)0.6%top 50.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/traefik/traefik	no fix listed	GHSA-cxjq-mrr5-89rv
Go	github.com/traefik/traefik	no fix listed	GO-2026-6208
Go	github.com/traefik/traefik/v2	2.11.52	GHSA-cxjq-mrr5-89rv
Go	github.com/traefik/traefik/v2	2.11.52	GO-2026-6208
Go	github.com/traefik/traefik/v3	3.7.7	GHSA-cxjq-mrr5-89rv
Go	github.com/traefik/traefik/v3	3.6.23, 3.7.7	GO-2026-6208
Go	github.com/traefik/traefik/v3	3.6.23	GHSA-cxjq-mrr5-89rv

Affected products (as reported)

Vendor	Product	Versions
traefik	traefik	0 – before 2.11.52
traefik	traefik	3.6.0 – before 3.6.23
traefik	traefik	3.7.0 – before 3.7.7

Weakness: CWE-22 · Vector: 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

References

GitHub Security Advisory (GHSA-cxjq-mrr5-89rv) vendor-advisory
VulnCheck Advisory: Traefik before v2.11.52 Authentication Bypass via ReplacePathRegex third-party-advisory