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CVE-2026-33151

HIGHCVSS 7.5/10EPSS 0.51%

Last modified

CVE-2026-33151 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.51% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

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

CVSS 4.0
8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.51%

39.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
SocketSocket.Io-Parser< 3.3.5
SocketSocket.Io-Parser>= 3.4.0, < 3.4.4
SocketSocket.Io-Parser>= 4.0.0, < 4.2.6

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-33151?
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.
How severe is CVE-2026-33151?
CVE-2026-33151 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.51% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33151?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST