node-server · Vulnerability

@hono/node-server allows running the Hono application on Node.js. From 2.0.0 until 2.1.6, the WebSocket upgrade handler waits for the Hono application to finish asynchronous middleware or handler work without first attaching an error listener to the socket. If an unauthenticated client resets the TCP connection during that window, the socket emits an unhandled ECONNRESET error and terminates the Node.js process. If a global uncaughtException handler suppresses termination, the pending upgrade waiter is not released and repeated requests can grow the heap. This affects applications that enable WebSocket support and perform asynchronous work on the upgrade path. This issue is fixed in version 2.1.6.

@hono/node-server allows running the Hono application on Node.js. From 2.0.0 until 2.1.6, the WebSocket upgrade handler waits for the Hono application to finish asynchronous middleware or handler work without first attaching an error listener to the socket. If an unauthenticated client resets the TCP connection during that window, the socket emits an unhandled ECONNRESET error and terminates the Node.js process. If a global uncaughtException handler suppresses termination, the pending upgrade waiter is not released and repeated requests can grow the heap. This affects applications that enable WebSocket support and perform asynchronous work on the upgrade path. This issue is fixed in version 2.1.6.

@hono/node-server allows running the Hono application on Node.js. From 2.0.0 until 2.1.6, the WebSocket upgrade handler waits for the Hono application to finish asynchronous middleware or handler work without first attaching an error listener to the socket. If an unauthenticated client resets the TCP connection during that window, the socket emits an unhandled ECONNRESET error and terminates the Node.js process. If a global uncaughtException handler suppresses termination, the pending upgrade waiter is not released and repeated requests can grow the heap. This affects applications that enable WebSocket support and perform asynchronous work on the upgrade path. This issue is fixed in version 2.1.6.

### Summary While `@hono/node-server` waits for the Hono application to handle a WebSocket upgrade request, the socket has no error listener. If the client resets the TCP connection during that time, the resulting `ECONNRESET` is emitted as an unhandled `'error'` event and the process terminates. ### Details The upgrade handler awaits the application before attaching any listener to the socket. When middleware on the upgrade path does asynchronous work, such as an authentication lookup, a connection reset in that window has no handler. If a global `uncaughtException` handler swallows the error, the pending upgrade is never released and its entry is retained for the lifetime of the process. The fix attaches error and close listeners to the socket before calling the application, releases the pending upgrade when the socket closes, and skips the handshake on a destroyed socket. ### Impact An unauthenticated client can terminate the server process with a single connection by sending a WebSocket upgrade request and resetting the connection before the application has responded. Where the crash is suppressed, repeated requests grow the heap. This affects applications that enable WebSocket support in `@hono/node-server` and run asynchronous middleware or handlers on the upgrade path.