Granian vulnerable to unauthenticated DoS via WebSocket subprotocol header panic
Granian aborts a worker process when an unauthenticated client sends a WebSocket upgrade request whose Sec-WebSocket-Protocol header contains non-ASCII bytes. The crash happens in Granian's WebSocket scope construction path, before the ASGI application is invoked. This is a single-request Denial Of Service against one worker. Repeating the request across workers takes the service offline.