CVE-2025-66490 Details
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.
A vulnerability exists in Traefik versions prior to 2.11.32 and 3.6.2, allowing requests with URL-encoded restricted characters to bypass path normalization. This issue can lead to path-based routing vulnerabilities, where requests skip the intended middleware and reach unintended backends. For example, a request to an admin path could bypass security controls and access a backend service directly. This vulnerability is fixed in Traefik versions 2.11.32 and 3.6.4.
Users can upgrade to Traefik versions 2.11.32 or 3.6.4 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Dec 9, 2025References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c | CISA-ADP | ExploitVendor Advisory |
| https://github.com/traefik/traefik/releases/tag/v2.11.32 | [email protected] | Release Notes |
| https://github.com/traefik/traefik/releases/tag/v3.6.4 | [email protected] | Release Notes |
| https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c | [email protected] | ExploitVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
| CWE-436 | Interpretation Conflict | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| traefik traefik | < 2.11.32 >= 3.0.0, < 3.6.3 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 6, 2026 | Reanalysis | [email protected] |
| Dec 11, 2025 | Initial Analysis | [email protected] |
| Dec 9, 2025 | CVE Modified | CISA-ADP |
| Dec 9, 2025 | New CVE Received | [email protected] |