What’s Vulnerable › Vulnerabilities

CVE-2024-38355: Unhandled 'error' event in socket.io

• Severity: high (CVSS 7.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-06-19 · updated 2026-06-17
• Weakness: CWE-20

Description

Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. A specially crafted Socket.IO packet can trigger an uncaught exception on the Socket.IO server, thus killing the Node.js process. This issue is fixed by commit `15af22fc22` which has been included in `socket.io@4.6.2` (released in May 2023). The fix was backported in the 2.x branch as well with commit `d30630ba10`. Users are advised to upgrade. Users unable to upgrade may attach a listener for the "error" event to catch these errors.

Affected products

• socketio socket.io: before 2.5.1; from 3.0.0 before 4.6.2 — fixed in 2.5.1, 4.6.2

How to fix

Upgrade to a fixed version: socketio socket.io 2.5.1, 4.6.2. Check the vendor advisory for mitigations.

References

• https://github.com/socketio/socket.io/commit/15af22fc22bc6030fcead322c106f07640336115
• https://github.com/socketio/socket.io/commit/d30630ba10562bf987f4d2b42440fc41a828119c
• https://github.com/socketio/socket.io/security/advisories/GHSA-25hc-qcg6-38wj
• https://github.com/socketio/socket.io/commit/15af22fc22bc6030fcead322c106f07640336115
• https://github.com/socketio/socket.io/commit/d30630ba10562bf987f4d2b42440fc41a828119c
• https://github.com/socketio/socket.io/security/advisories/GHSA-25hc-qcg6-38wj
• https://www.vicarius.io/vsociety/posts/unhandled-exception-in-socketio-cve-2024-38355

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