@HONO/NODE-SERVER · CVE-2026-126343 · Package
FIX → 2.1.6
When a WebSocket upgrade request is waiting on async Hono middleware, a client resetting the TCP connection raises an unhandled ECONNRESET error. The Node process terminates, and if the crash is suppressed, memory grows with repeated requests.
first public Nov 2, 2026 · 2 sources
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Applications that enable WebSocket support in @hono/node-server and run asynchronous middleware or handlers on the upgrade path are exposed. The sources say a single unauthenticated connection reset can crash the server, so internet-facing WebSocket endpoints are the main concern. Applications without WebSocket support enabled, or with no async work on the upgrade path, are not described as affected.
Not affected if no-async-upgrade-middleware, no-websocket-support
Who cares hono, node, self-hosted, websocket
npm ls @hono/node-server@hono/node-server and async middleware or handlers on the upgrade pathuncaughtException handler is registered in the appUpgrade to 2.1.6
@hono/node-server or later (fixed in for affected )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.
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.
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.
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2.1.62.1.6>= 2.0.0, < 2.1.6This page as .md · .json · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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