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Vulnerability record · CVE-2023-31125 · published 8 May 2023

CVE-2023-31125: Socket engine.io vulnerability

Socket · Engine.Io

Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability 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. 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, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.

6.5 CVSS 3.1 Medium EPSS 1.3% · top 30.2% CWE-248 · CWE-248
6.5CVSS 3.1 base score
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability 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. 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, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/socketio/engine.io/commit/fc480b4f305e16fe5972cf337d055e598372dc44 Patch
https://github.com/socketio/engine.io/releases/tag/6.4.2 Release Notes
https://github.com/socketio/engine.io/security/advisories/GHSA-q9mw-68c2-j6m5 Vendor Advisory
https://security.netapp.com/advisory/ntap-20230622-0002/
https://github.com/socketio/engine.io/commit/fc480b4f305e16fe5972cf337d055e598372dc44 Patch
https://github.com/socketio/engine.io/releases/tag/6.4.2 Release Notes
https://github.com/socketio/engine.io/security/advisories/GHSA-q9mw-68c2-j6m5 Vendor Advisory
https://security.netapp.com/advisory/ntap-20230622-0002/

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2026-59725Socket engine.io improper resource shutdown vulnerabilitySocket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport do…EPSS 0.64%7.5CVE-2026-59724Socket engine.io improper input validation vulnerabilitySocket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enable…EPSS 0.61%7.5CVE-2022-21676Socket engine.io vulnerabilityEngine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted H…EPSS 2.8%7.5CVE-2020-36048Socket engine.io uncontrolled resource consumption vulnerabilityEngine.IO before 4.0.0 allows attackers to cause a denial of service (resource consumption) via a POST request to the long polling transport.EPSS 3.2%6.5CVE-2022-41940Socket engine.io vulnerabilityEngine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted H…EPSS 2.1%

Source: NIST National Vulnerability Database (record CVE-2023-31125), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.