undici: undici: Denial of Service via unrequested WebSocket subprotocol

A flaw was found in undici. A remote attacker can exploit this vulnerability by responding with an unrequested WebSocket subprotocol during the opening handshake. This causes the undici WebSocket client to crash the entire Node.js process, leading to a denial of service DoS...

CVE-2026-19534 undici vulnerable to Denial of Service via unrequested WebSocket subprotocol

undici's WebSocket client crashes the whole Node.js process during the opening handshake when a server responds with a subprotocol that the client never requested. A default WebSocket connection sends no subprotocol, but if the server's 101 response includes a Sec-WebSocket-Protocol header, undic...