CVE-2022-21676
Uncaught Exception in engine.io
Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. 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. Versions prior to 4.0.0 are not impacted. A fix has been released for each major branch, namely 4.1.2 for the 4.x.x branch, 5.2.1 for the 5.x.x branch, and 6.1.1 for the 6.x.x branch. There is no known workaround except upgrading to a safe version.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
Uncaught Exception in engine.io
Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. 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. Versions prior to 4.0.0 are not impacted. A fix has been released for each major branch, namely 4.1.2 for the 4.x.x branch, 5.2.1 for the 5.x.x branch, and 6.1.1 for the 6.x.x branch. There is no known workaround except upgrading to a safe version.
- Record
CVE-2022-21676- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-754
- Updated
- 2026-11-02
EUVDEUVD-2022-0421
7.5
Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. 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. Versions prior to 4.0.0 are not impacted. A fix has been released for each major branch, namely 4.1.2 for the 4.x.x branch, 5.2.1 for the 5.x.x branch, and 6.1.1 for the 6.x.x branch. There is no known workaround except upgrading to a safe version.
- Record
EUVD-2022-0421- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-273r-mgr4-v34f
7.5
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 |
| --- | --- |
| [email protected] | 4.1.2 |
| [email protected] | 5.2.1 |
| [email protected] | 6.1.1 |
Previous versions (< 4.0.0) are not impacted.
For socket.io users:
| Version range | engine.io version | Needs minor update? |
| --- | --- | --- |
| [email protected] | ~6.1.0 | -
| [email protected] | ~6.0.0 | Please upgrade to [email protected]
| [email protected] | ~5.2.0 | -
| [email protected] | ~5.1.1 | Please upgrade to [email protected]
| [email protected] | ~5.0.0 | Please upgrade to [email protected]
| [email protected] | ~4.1.0 | -
| [email protected] | ~4.0.0 | Please upgrade to [email protected] or [email protected] (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.
- Record
GHSA-273r-mgr4-v34f- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-754, CWE-755
- Updated
- 2026-11-02
NVD
7.5
Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. 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. Versions prior to 4.0.0 are not impacted. A fix has been released for each major branch, namely 4.1.2 for the 4.x.x branch, 5.2.1 for the 5.x.x branch, and 6.1.1 for the 6.x.x branch. There is no known workaround except upgrading to a safe version.
- Record
CVE-2022-21676- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-754, CWE-755
- Updated
- 2026-11-02
OSV
7.5
Uncaught Exception in engine.io
Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. 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. Versions prior to 4.0.0 are not impacted. A fix has been released for each major branch, namely 4.1.2 for the 4.x.x branch, 5.2.1 for the 5.x.x branch, and 6.1.1 for the 6.x.x branch. There is no known workaround except upgrading to a safe version.
- Record
CVE-2022-21676- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-754
- Updated
- 2026-11-02
OSVGHSA-273r-mgr4-v34f
7.5
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 |
| --- | --- |
| [email protected] | 4.1.2 |
| [email protected] | 5.2.1 |
| [email protected] | 6.1.1 |
Previous versions (< 4.0.0) are not impacted.
For socket.io users:
| Version range | engine.io version | Needs minor update? |
| --- | --- | --- |
| [email protected] | ~6.1.0 | -
| [email protected] | ~6.0.0 | Please upgrade to [email protected]
| [email protected] | ~5.2.0 | -
| [email protected] | ~5.1.1 | Please upgrade to [email protected]
| [email protected] | ~5.0.0 | Please upgrade to [email protected]
| [email protected] | ~4.1.0 | -
| [email protected] | ~4.0.0 | Please upgrade to [email protected] or [email protected] (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.
- Record
GHSA-273r-mgr4-v34f- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-754, CWE-755
- Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2022-21676 is a high vulnerability (CVSS 7.5) in Socket Engine.io, published January 12, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.85%, the 86th percentile. Fixed in engine.io 4.1.2.
References
github.com/socketio/engine.io/security/advisories/GHSA-273r-mgr4-v34f
github.com/socketio/engine.io/commit/66f889fc1d966bf5bfa0de1939069153643874ab
github.com/socketio/engine.io/commit/a70800d7e96da32f6e6622804ef659ebc58659db
github.com/socketio/engine.io/commit/c0e194d44933bd83bf9a4b126fca68ba7bf5098c
github.com/socketio/engine.io/releases/tag/4.1.2
github.com/socketio/engine.io/releases/tag/5.2.1