socket.io has an unhandled 'error' event
Impact
A specially crafted Socket.IO packet can trigger an uncaught exception on the Socket.IO server, thus killing the Node.js process.
node:events:502
throw err; // Unhandled 'error' event
^
Error [ERR_UNHANDLED_ERROR]: Unhandled error. (undefined)
at new NodeError (node:internal/errors:405:5)
at Socket.emit (node:events:500:17)
at /myapp/node_modules/socket.io/lib/socket.js:531:14
at process.processTicksAndRejections (node:internal/process/task_queues:77:11) {
code: 'ERR_UNHANDLED_ERROR',
context: undefined
}Affected versions
| Version range | Needs minor update? |
|---|---|
4.6.2...latest |
Nothing to do |
3.0.0...4.6.1 |
Please upgrade to socket.io@4.6.2 (at least) |
2.3.0...2.5.0 |
Please upgrade to socket.io@2.5.1 |
Patches
This issue is fixed by https://github.com/socketio/socket.io/commit/15af22fc22bc6030fcead322c106f07640336115, included in socket.io@4.6.2 (released in May 2023).
The fix was backported in the 2.x branch today: https://github.com/socketio/socket.io/commit/d30630ba10562bf987f4d2b42440fc41a828119c
Workarounds
As a workaround for the affected versions of the socket.io package, you can attach a listener for the "error" event:
io.on("connection", (socket) => {
socket.on("error", () => {
// ...
});
});For more information
If you have any questions or comments about this advisory:
- Open a discussion here
Thanks a lot to Paul Taylor for the responsible disclosure.
References
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | socket.io | < 2.5.1, >= 3.0.0, < 4.6.2 | 2.5.1, 4.6.2 |
References
- https://github.com/socketio/socket.io/security/advisories/GHSA-25hc-qcg6-38wj
- https://nvd.nist.gov/vuln/detail/CVE-2024-38355
- https://github.com/socketio/socket.io/commit/15af22fc22bc6030fcead322c106f07640336115
- https://github.com/socketio/socket.io/commit/d30630ba10562bf987f4d2b42440fc41a828119c
- https://github.com/socketio/socket.io
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L- Weakness (CWE)
CWE-20, CWE-754- Platform
- npm
- Package
socket.io- Disclosed
- 19.06.2024
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-25hc-qcg6-38wj - CC BY 4.0
Vulnerability history: socket.io
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 11.2018 06.2024
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 2
Disclosures per year
- 2018: 1
- 2019: 0
- 2020: 0
- 2021: 1
- 2022: 0
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 0
-
socket.io has an unhandled 'error' event this entry
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