Vulnerability · Published Jul 22, 2026 · Assigned by VulnCheck

CVE-2026-65601Traefik before 3.7.7 Namespace Confusion via HTTPRoute ExtensionRef

Medium 5.3

In plain English

A medium-severity incorrect authorization 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 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.5%top 56.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Traefik versions 3.7.0 through 3.7.6 contain a namespace confusion vulnerability in the Kubernetes Gateway API provider. When resolving HTTPRoute.spec.rules[].backendRefs[].filters[].extensionRef, Traefik used the backend Service namespace instead of the HTTPRoute namespace. A low-privileged route author holding a ReferenceGrant for a cross-namespace Service could therefore bind a Traefik Middleware from the backend namespace without a separate grant for that middleware, potentially injecting trusted reverse-proxy identity headers into downstream requests. The issue is fixed in version 3.7.7.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	Traefik	3.7.7	GHSA-qq9q-x9w4-chhj
Go	github.com/traefik/traefik	no fix listed	GO-2026-6198

Affected products (as reported)

Vendor	Product	Versions
traefik	traefik	3.7.0 – before 3.7.7

Weakness: CWE-863 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

References

GitHub Security Advisory (GHSA-qq9q-x9w4-chhj) vendor-advisory
Patch Commit patch
VulnCheck Advisory: Traefik before 3.7.7 Namespace Confusion via HTTPRoute ExtensionRef third-party-advisory