# CVE-2026-65601: Traefik namespace confusion in Kubernetes Gateway API extensionRef

Source: https://junglewise.ai/threats/cve-2026-65601-traefik-namespace-confusion-in-kubernetes-gateway-api  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-22. Updated: 2026-08-05  
License: CC BY 4.0 with a link back

CVE-2026-65601 · Severity: medium · CVSS 4 · Published 2026-07-22

Traefik, a popular cloud-native application proxy and load balancer, contains a vulnerability in how it handles traffic rules in Kubernetes environments. An attacker with limited permissions to create network routes could trick the system into applying security settings (middlewares) from a different, more privileged area of the network. This could allow the attacker to bypass authentication or impersonate other users in downstream applications like Grafana or Jenkins by injecting unauthorized identity headers.

Technologies: [github.com/traefik/traefik (Go)](https://junglewise.ai/threats/technologies/github-com-traefik-traefik), [Traefik Labs Traefik Proxy](https://junglewise.ai/threats/technologies/traefik-proxy). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Traefik Labs](https://junglewise.ai/threats/vendors/traefik-labs).

## Quick answers

**Is CVE-2026-65601 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-65601 being exploited in the wild.

**How severe is CVE-2026-65601?** Medium severity, with a CVSS score of 4, published 22 July 2026.

**Which products and versions are affected?** github.com/traefik/traefik (Go) SEMVER:introduced=0; Traefik (Go) SEMVER:introduced=3.7.0,fixed=3.7.7; Traefik Labs Traefik Proxy 3.7.0 to 3.7.6.

**Is there a fix for CVE-2026-65601?** Yes. Traefik (Go): upgrade to 3.7.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-65601 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-65601?** Check whether you run github.com/traefik/traefik (Go), Traefik (Go) or Traefik Labs Traefik Proxy at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Traefik (Go): upgrade to 3.7.7 or later

  ```sh
  go get Traefik@v3.7.7
  ```


## Technical details

A namespace-confusion vulnerability exists in Traefik's Kubernetes Gateway API provider when resolving 'HTTPRoute.spec.rules[].backendRefs[].filters[].extensionRef'. The root cause is that Traefik incorrectly reuses the backend Service's namespace instead of the HTTPRoute's namespace when resolving extension filters. A low-privileged attacker with 'ReferenceGrant' access to a cross-namespace Service can bind a Traefik 'Middleware' from that backend namespace without explicit authorization. If the bound middleware is configured to inject identity headers (e.g., X-WEBAUTH-USER), the attacker can achieve unauthorized authenticated state in downstream applications. This issue is fixed in version 3.7.7.

## Affected products

- Traefik Labs Traefik >= 3.7.0, < 3.7.7

## Identifiers

- CVE-2026-65601
- GHSA-qq9q-x9w4-chhj
- GO-2026-6198

## Timeline

- 2026-07-09: advisory: Initial GitHub Advisory published
- 2026-08-05: patched: Fix released in version 3.7.7

## References

- [https://api.github.com/users/CuB3y0nd](https://api.github.com/users/CuB3y0nd)
- [https://github.com/CuB3y0nd](https://github.com/CuB3y0nd)
- [https://api.github.com/users/CuB3y0nd/gists%7B/gist_id%7D](https://api.github.com/users/CuB3y0nd/gists%7B/gist_id%7D)
- [https://api.github.com/users/CuB3y0nd/repos](https://api.github.com/users/CuB3y0nd/repos)
- [https://avatars.githubusercontent.com/u/91041570?v=4](https://avatars.githubusercontent.com/u/91041570?v=4)
- [https://api.github.com/users/CuB3y0nd/events%7B/privacy%7D](https://api.github.com/users/CuB3y0nd/events%7B/privacy%7D)

## Related threats

- [Traefik BasicAuth singleflight username enumeration via timing oracle](https://junglewise.ai/threats/cve-2026-88010-traefik-basicauth-singleflight-username-enumeration-via-timing)
- [Traefik readTimeout not enforced on HTTP/3 connections](https://junglewise.ai/threats/cve-2026-88012-traefik-readtimeout-not-enforced-on-http-3-connections)
- [Traefik ForwardAuth identity spoofing via header alias](https://junglewise.ai/threats/cve-2026-88011-traefik-forwardauth-identity-spoofing-via-header-alias)
- [Traefik rootless HTTP/1 request-target routing bypass](https://junglewise.ai/threats/cve-2026-88009-traefik-rootless-http-1-request-target-routing-bypass)
- [Traefik HTTP request smuggling via unrestricted protocol upgrade](https://junglewise.ai/threats/cve-2026-88008-traefik-http-request-smuggling-via-unrestricted-protocol-upgrade)