Read the docs
TI-2025-40914 Aliases CVE-2025-66490GHSA-gm3x-23wp-hc2c

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

Priority HIGH 70CWE-436Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00439 38th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed github.com/traefik/traefik/v2 (Go): 2.11.32github.com/traefik/traefik/v3 (Go): 3.6.3Red Hat: 1 advisory

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
traefiktraefikgithub.com/traefik/traefik/v3 < 3.6.3; github.com/traefik/traefik/v2 < 2.11.32; github.com/traefik/traefik <= 1.7.34—No fix listedCNA
—github.com/traefik/traefik (Go)up to 1.7.34—No fix listedGHSA-gm3x-23wp-hc2c
—github.com/traefik/traefik/v2 (Go)before 2.11.322.11.32Patch availableGHSA-gm3x-23wp-hc2c
—github.com/traefik/traefik/v3 (Go)before 3.6.33.6.3Patch availableGHSA-gm3x-23wp-hc2c
  • traefik Vendortraefik Affected github.com/traefik/traefik/v3 < 3.6.3; github.com/traefik/traefik/v2 < 2.11.32; github.com/traefik/traefik <= 1.7.34 Fixed in — No fix listed CNA
  • github.com/traefik/traefik (Go) Vendor— Affected up to 1.7.34 Fixed in — No fix listed GHSA-gm3x-23wp-hc2c
  • github.com/traefik/traefik/v2 (Go) Vendor— Affected before 2.11.32 Fixed in 2.11.32 Patch available GHSA-gm3x-23wp-hc2c
  • github.com/traefik/traefik/v3 (Go) Vendor— Affected before 3.6.3 Fixed in 3.6.3 Patch available GHSA-gm3x-23wp-hc2c

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*before 2.11.32; 3.0.0 to before 3.6.3Vulnerabletraefik
  • cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* Versions before 2.11.32; 3.0.0 to before 3.6.3 Vulnerable ·traefik

Remediation

  • Fix · GHSA-gm3x-23wp-hc2c github.com/traefik/traefik/v2 (Go) Fixed in 2.11.32 Advisory →
  • Fix · GHSA-gm3x-23wp-hc2c github.com/traefik/traefik/v3 (Go) Fixed in 3.6.3 Advisory →

Red Hat 1 advisory

  • RHSA-2026:2456 Released 2026-02-10 · Red Hat rating Important
    Red Hat OpenShift Dev Spaces 3.26.0 Release.
    • Red Hat OpenShift Dev Spaces (RHOSDS) 3.26 registry.redhat.io/devspaces/code-rhel9, registry.redhat.io/devspaces/configbump-rhel9, registry.redhat.io/devspaces/dashboard-rhel9 +9

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat OpenShift Dev Spaces (RHOSDS) 3.26Fixed RHSA-2026:2456
Not affected: 1 product
  • Red Hat OpenShift Dev Spaces (RHOSDS) 3.26

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-66490
  2. 2026-10-03 Alias added: GHSA-gm3x-23wp-hc2c

References

Exploit 1

Advisory 1

Other 3

  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2023-25774 Uncontrolled Resource Consumption in Traefik CVSS 3.1HIGH 7.5
  • TI-2022-07529 Authorization header displayed in the debug logs CVSS 3.1MEDIUM 6.5
  • TI-2024-30459 HTTP client can remove the X-Forwarded headers in Traefik CVSS 3.1CRITICAL 9.8
  • TI-2026-60261 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect CVSS 4.0CRITICAL 9.3
  • TI-2026-60033 Traefik HTTP/3 Backend NTLM Connection Reuse CVSS 4.0CRITICAL 9.1
See all 83 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences