Traefik path traversal in Kubernetes Ingress NGINX RewriteTarget

Severity: high · CVSS 7.8 · Published 2026-08-01

Traefik, a popular cloud-native application proxy, contains a vulnerability in how it handles specific URL rewriting rules for Kubernetes environments. An attacker can craft a malicious web request that tricks the system into bypassing security controls like login screens or access restrictions. This could allow unauthorized access to sensitive administrative data or internal services that were intended to be protected.

Technologies: github.com/traefik/traefik/v3 (Go), Traefik Labs Traefik Proxy. Vendors: Go, Traefik Labs.

Quick answers

Is This vulnerability exploited in the wild?
No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?
High severity, with a CVSS score of 7.8, published 1 August 2026.
Which products and versions are affected?
github.com/traefik/traefik/v3 (Go) >= 3.7.0, <= 3.7.7; Traefik Labs Traefik Proxy >= v3.7.0, <= v3.7.7.
Is there a fix for This vulnerability?
A patch was published on 2026-08-06: Duplicate advisory withdrawn in favor of original GHSA-8rxv-jg7p-wvg3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?
It is attacked over the network, in a software library.
Am I affected?
Check whether you run github.com/traefik/traefik/v3 (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.

Technical details

A path traversal vulnerability exists in Traefik's Kubernetes Ingress NGINX provider's RewriteTarget middleware. When an Ingress path uses a regex that captures attacker-controlled text without requiring a path separator (e.g., /api(.*) with rewrite target /$1), a crafted request like /api../admin is rewritten to /../admin. Because Traefik forwards this rewritten path without post-replacement normalization validation, a backend that normalizes dot segments will resolve the path to a protected endpoint (e.g., /admin). This allows an attacker to bypass middlewares such as BasicAuth, DigestAuth, or ForwardAuth that are attached to the intended protected router. The issue is fixed in v3.7.8.

Affected products

  • Traefik Labs Traefik >= v3.7.0, <= v3.7.7

Timeline

  • 2026-07-16: advisory: Original advisory GHSA-8rxv-jg7p-wvg3 published
  • 2026-08-01: disclosed: Duplicate advisory GHSA-7qf5-7ppr-87v8 published
  • 2026-08-06: patched: Duplicate advisory withdrawn in favor of original GHSA-8rxv-jg7p-wvg3

References

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