CVE-2026-44985: Dozzle's Cross-Site WebSocket Hijacking (CSWSH) on exec/attach endpointsbypasses authentication

The WebSocket upgrader for the /exec and /attach endpoints uses CheckOrigin: func(r *http.Request) bool { return true }, accepting upgrade requests from any origin. Combined with the JWT cookie using SameSite: Lax, this enables Cross-Site WebSocket Hijacking (CSWSH) — even when authentication is properly configured.

An attacker hosting a page on a same-site origin (e.g., a sibling subdomain, or another service on localhost) can initiate a WebSocket connection to the exec endpoint that carries the victim’s valid JWT cookie, gaining interactive shell access in any container the victim is authorized to access.