CVE-2026-33151
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductSocket.io-parser
PublishedMar 20, 2026
First seenMar 20, 2026
Weakness typeCWE-20Improper input validationCWE-754CWE-754
How to fix
Update
- socket socket.io-parser3.3.5, 3.4.4, 4.2.6 or later
- socket.io-parser3.3.5, 3.4.4, 4.2.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| socket socket.io-parser | v < 3.3.5, 3.4.0 ≤ v < 3.4.4, 4.0.0 ≤ v < 4.2.6 | 3.3.5, 3.4.4, 4.2.6 |
| socket.io-parsernpm | v < 3.3.5, 3.4.0 ≤ v < 3.4.4, 4.0.0 ≤ v < 4.2.6 | 3.3.5, 3.4.4, 4.2.6 |
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