CVE-2026-33151

HIGH

socket.io allows an unbounded number of binary attachments

Title source: cna
STIX 2.1

Description

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.

References (4)

Core 4

Scores

CVSS v3 7.5
EPSS 0.0051
EPSS Percentile 39.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-20 CWE-754
Status published
Products (5)
npm/socket.io-parser 0 - 3.3.5npm
socket/socket.io-parser < 3.3.5
socketio/socket.io < 3.3.5
socketio/socket.io >= 3.4.0, < 3.4.4
socketio/socket.io >= 4.0.0, < 4.2.6
Published Mar 20, 2026
Tracked Since Mar 21, 2026