Uncaught Exception in engine.io
Impact
A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process.
RangeError: Invalid WebSocket frame: RSV2 and RSV3 must be clear at Receiver.getInfo (/.../node_modules/ws/lib/receiver.js:176:14) at Receiver.startLoop (/.../node_modules/ws/lib/receiver.js:136:22) at Receiver._write (/.../node_modules/ws/lib/receiver.js:83:10) at writeOrBuffer (internal/streams/writable.js:358:12)
This impacts all the users of the engine.io package starting from version 4.0.0, including those who uses depending packages like socket.io.
Patches
A fix has been released for each major branch:
| Version range | Fixed version |
|---|---|
engine.io@4.x.x |
4.1.2 |
engine.io@5.x.x |
5.2.1 |
engine.io@6.x.x |
6.1.1 |
Previous versions (< 4.0.0) are not impacted.
For socket.io users:
| Version range | engine.io version |
Needs minor update? |
|---|---|---|
socket.io@4.4.x |
~6.1.0 |
- |
socket.io@4.3.x |
~6.0.0 |
Please upgrade to socket.io@4.4.x |
socket.io@4.2.x |
~5.2.0 |
- |
socket.io@4.1.x |
~5.1.1 |
Please upgrade to socket.io@4.4.x |
socket.io@4.0.x |
~5.0.0 |
Please upgrade to socket.io@4.4.x |
socket.io@3.1.x |
~4.1.0 |
- |
socket.io@3.0.x |
~4.0.0 |
Please upgrade to socket.io@3.1.x or socket.io@4.4.x (see here) |
In most cases, running npm audit fix should be sufficient. You can also use npm update engine.io --depth=9999.
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
Thanks to Marcus Wejderot from Mevisio for the responsible disclosure.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | engine.io | >= 4.0.0, < 4.1.2, >= 5.0.0, < 5.2.1, >= 6.0.0, < 6.1.1 | 4.1.2, 5.2.1, 6.1.1 |
References
- https://github.com/socketio/engine.io/security/advisories/GHSA-273r-mgr4-v34f
- https://nvd.nist.gov/vuln/detail/CVE-2022-21676
- https://github.com/socketio/engine.io/commit/66f889fc1d966bf5bfa0de1939069153643874ab
- https://github.com/socketio/engine.io/commit/a70800d7e96da32f6e6622804ef659ebc58659db
- https://github.com/socketio/engine.io/commit/c0e194d44933bd83bf9a4b126fca68ba7bf5098c
- https://github.com/socketio/engine.io
- https://github.com/socketio/engine.io/releases/tag/4.1.2
- https://github.com/socketio/engine.io/releases/tag/5.2.1
- https://github.com/socketio/engine.io/releases/tag/6.1.1
- https://security.netapp.com/advisory/ntap-20220209-0002
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-754, CWE-755- Platform
- npm
- Package
engine.io- Disclosed
- 13.01.2022
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-273r-mgr4-v34f - CC BY 4.0
Vulnerability history: engine.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
- 7
- First → latest
- 01.2022 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 5
- Medium 2
Disclosures per year
- 2022: 3
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 3
-
Uncaught Exception in engine.io this entry
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