Impact

A specially crafted Socket.IO packet can trigger an uncaught exception on the Socket.IO server, thus killing the Node.js process.

TypeError: Cannot convert object to primitive value at Socket.emit (node:events:507:25) at .../nodemodules/socket.io/lib/socket.js:531:14

Patches

A fix has been released today (2023/05/22):

- https://github.com/socketio/socket.io-parser/commit/3b78117bf6ba7e99d7a5cfc1ba54d0477554a7f3, included in socket.io-parser@4.2.3 - https://github.com/socketio/socket.io-parser/commit/2dc3c92622dad113b8676be06f23b1ed46b02ced, included in socket.io-parser@3.4.3

Another fix has been released for the 3.3.x branch:

- https://github.com/socketio/socket.io-parser/commit/ee006607495eca4ec7262ad080dd3a91439a5ba4, included in socket.io-parser@3.3.4

| socket.io version | socket.io-parser version | Needs minor update? | |---------------------|---------------------------------------------------------------------------------------------------------|--------------------------------------| | 4.5.2...latest | ~4.2.0 (ref) | npm audit fix should be sufficient | | 4.1.3...4.5.1 | ~4.1.1 (ref) | Please upgrade to socket.io@4.6.x | | 3.0.5...4.1.2 | ~4.0.3 (ref) | Please upgrade to socket.io@4.6.x | | 3.0.0...3.0.4 | ~4.0.1 (ref) | Please upgrade to socket.io@4.6.x | | 2.3.0...2.5.0 | ~3.4.0 (ref) | npm audit fix should be sufficient |

Workarounds

There is no known workaround except upgrading to a safe version.

For more information

If you have any questions or comments about this advisory:

- Open a discussion here

Thanks to @rafax00 for the responsible disclosure.