VYPR
Moderate severityNVD Advisory· Published Dec 9, 2025· Updated Dec 9, 2025

Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules

CVE-2025-66490

Description

Traefik is an HTTP reverse proxy and load balancer. For versions prior to 2.11.32 and 2.11.31 through 3.6.2, requests using PathPrefix, Path or PathRegex matchers can bypass path normalization. When Traefik uses path-based routing, requests containing URL-encoded restricted characters (/, \, Null, ;, ?, #) can bypass the middleware chain and reach unintended backends. For example, a request to http://mydomain.example.com/admin%2F could reach service-a without triggering my-security-middleware, bypassing security controls for the /admin/ path. This issue is fixed in versions 2.11.32 and 3.6.3.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
github.com/traefik/traefikGo
<= 1.7.34
github.com/traefik/traefik/v2Go
< 2.11.322.11.32
github.com/traefik/traefik/v3Go
< 3.6.33.6.3

Affected products

9

Patches

Vulnerability mechanics

References

5

News mentions

0

No linked articles in our index yet.