GHSA-q9mw-68c2-j6m5

### Impact

A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process.

``` TypeError: Cannot read properties of undefined (reading 'handlesUpgrades') at Server.onWebSocket (build/server.js:515:67) ```

This impacts all the users of the [`engine.io`](https://www.npmjs.com/package/engine.io) package, including those who uses depending packages like [`socket.io`](https://www.npmjs.com/package/socket.io).

### Patches

A fix has been released today (2023/05/02): [6.4.2](https://github.com/socketio/engine.io/releases/tag/6.4.2)

This bug was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted.

For `socket.io` users:

| Version range | `engine.io` version | Needs minor update? | |-----------------------------|---------------------|--------------------------------------------------------------------------------------------------------| | `socket.io@4.6.x` | `~6.4.0` | `npm audit fix` should be sufficient | | `socket.io@4.5.x` | `~6.2.0` | Please upgrade to `socket.io@4.6.x` | | `socket.io@4.4.x` | `~6.1.0` | Please upgrade to `socket.io@4.6.x` | | `socket.io@4.3.x` | `~6.0.0` | Please upgrade to `socket.io@4.6.x` | | `socket.io@4.2.x` | `~5.2.0` | Please upgrade to `socket.io@4.6.x` | | `socket.io@4.1.x` | `~5.1.1` | Please upgrade to `socket.io@4.6.x` | | `socket.io@4.0.x` | `~5.0.0` | Not impacted | | `socket.io@3.1.x` | `~4.1.0` | Not impacted | | `socket.io@3.0.x` | `~4.0.0` | Not impacted | | `socket.io@2.5.0` | `~3.6.0` | Not impacted | | `socket.io@2.4.x` and below | `~3.5.0` | Not impacted |

### 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 an issue in [`engine.io`](https://github.com/socketio/engine.io)

Thanks to Thomas Rinsma from Codean for the responsible disclosure.