GHSA-qq8j-7v2v-3rwp undici WebSocket client vulnerable to Denial of Service via failed HTTP/2 handshake

• npm undici: >= 8.11.0, < 8.11.2 → fixed in 8.11.2

Impact undici's experimental WebSocket client (enabled by default via `allowH2: true`) crashes the Node.js process when it connects to a malicious server over HTTP/2. If the server answers the WebSocket upgrade with a response that fails handshake validation, undici aborts the request, but the abort is a no-op because the request is already marked completed, so the underlying `ClientHttp2Stream` is left open with no error listener. When the server then destroys the connection, the orphaned stream emits an unhandled `error` and the process exits. A remote, unauthenticated server can therefore deny service to any client that opens a WebSocket to it over HTTP/2. undici 8.11.0 and 8.11.1 are affected; the regression was introduced in 8.11.0. Patches Upgrade to `8.11.2`. Workarounds Set `allowH2: false` to disable HTTP/2 for WebSocket connections, or avoid opening WebSocket connections to untrusted servers, until upgrading.