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 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.
- CVSS 4.0
- 6.9
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - CVSS 3.1
- 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 37% of CVEs (scores of 2026-10-25)
- CWE
- CWE-436
- Published
- Modified
- Record from
- the NVD, synced
Affected
- traefik:traefik
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-gm3x-23wp-hc2c | Go | github.com/traefik/traefik | <=1.7.34 | no fix published |
| GHSA-gm3x-23wp-hc2c | Go | github.com/traefik/traefik/v2 | <2.11.32 | 2.11.32 |
| GHSA-gm3x-23wp-hc2c | Go | github.com/traefik/traefik/v3 | <3.6.3 | 3.6.3 |
| GO-2025-4206 | Go | github.com/traefik/traefik | all versions | no fix published |
| GO-2025-4206 | Go | github.com/traefik/traefik/v2 | <2.11.32 | 2.11.32 |
| GO-2025-4206 | Go | github.com/traefik/traefik/v3 | <3.6.3 | 3.6.3 |