CVE-2025-66491
Fixed in a distro release EPSS <1%CVSS 5.9
Traefik is an HTTP reverse proxy and load balancer. Versions 3.5.0 through 3.6.2 have inverted TLS verification logic in the nginx.ingress.kubernetes.io/proxy-ssl-verify annotation. Setting the annotation to "on" (intending to enable backend TLS certificate verification) actually disables verification, allowing man-in-the-middle attacks against HTTPS backends when operators believe they are protected. This issue is fixed in version 3.6.3.
Products: traefik
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Go | github.com/traefik/traefik | no fix |
| Go | github.com/traefik/traefik/v2 | no fix |
| Go | github.com/traefik/traefik/v3 | 3.6.3 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | traefik-3.5 | no fix |
| Chainguard | traefik-fips-2.11 | 2.11.51-r0 |
| Chainguard | traefik-fips-3.5 | no fix |
| openSUSE:Leap 15.6 | govulncheck-vulndb | 0.0.20251230T014957-150000.1.134.1 |
| openSUSE:Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 |
| openSUSE:Tumbleweed | traefik | 3.6.6-1.1 |