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CVE

CVE-2025-66490

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 us

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.

MEDIUM · CVSS 6.5 EPSS 0.00018
Schedule remediation
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0

Weakness Classification

Affected Products & Versions

2
traefik< 2.11.32
traefik>= 3.0.0 and < 3.6.3

Affected Packages

3
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go github.com/traefik/traefik MODERATE
Go github.com/traefik/traefik/v2 MODERATE fixed in 2.11.32
Go github.com/traefik/traefik/v3 MODERATE fixed in 3.6.3

Public Exploits & PoCs

1

Scoring & Timeline

6.5
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD09 Dec 2025 · 01:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.

Vendor Advisories

3
suse-csafopenSUSE-SU-2026:10143-1
rhsaRHSA-2026:2456Important
suse-csafopenSUSE-SU-2026:10020-1
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
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