CVE-2026-33151: Socket Socket.io-Parser

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. Prior to versions 3.3.5, 3.4.4, and 4.2.6, a specially crafted Socket.IO packet can make the server wait for a large number of binary attachments and buffer them, which can be exploited to make the server run out of memory. This issue has been patched in versions 3.3.5, 3.4.4, and 4.2.6.

Affected products

• Socket Socket.io-Parser: before 3.3.5 (fixed in 3.3.5); from 3.4.0, before 3.4.4 (fixed in 3.4.4); from 4.0.0, before 4.2.6 (fixed in 4.2.6)

Published 2026-03-20. Last modified 2026-06-17.