Auth bypass in Traefik Kubernetes ingress-nginx provider: Ingresses with auth annotations plus nginx.ingress.kubernetes.io/from-to-www-redirect create a sibling host-only router with only RedirectRegex but same backend. Crafted Host with non-numeric/empty port (e.g. www.example.com:x) bypasses redirect and all annotation middlewares (BasicAuth, IP allowlist). Affected traefik 3.7.0-3.7.11; Upgrade to 3.7.12 to mitigate.