Bug 2420303 (CVE-2025-66491) - CVE-2025-66491 github.com/traefik/traefik: Traefik has Inverted TLS Verification Logic in its ingress-nginx Provider
Summary: CVE-2025-66491 github.com/traefik/traefik: Traefik has Inverted TLS Verificat...
Keywords:
Status: NEW
Alias: CVE-2025-66491
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-12-09 01:07 UTC by OSIDB Bzimport
Modified: 2025-12-10 00:15 UTC (History)
1 user (show)

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Description OSIDB Bzimport 2025-12-09 01:07:11 UTC 
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.
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