TI-2026-25581 Aliases CVE-2026-33151 GHSA-677m-j7p3-52f9

socket.io allows an unbounded number of binary attachments

MEDIUM 44CWE-20Published 2026-03-20 · Updated 2026-03-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 3 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00535 45th percentileScored 2026-11-07

Fix Partial socket.io (socketio): 3.3.5, 3.4.4, 4.2.6socket.io-parser (npm): 3.3.5, 3.4.4, 4.2.6Red Hat: 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
socketio	socket.io	before 3.3.5; 3.4.0 to before 3.4.4; 4.0.0 to before 4.2.6	3.3.5, 3.4.4, 4.2.6	Patch available	CNA
—	socket.io-parser (npm)	before 3.3.5	3.3.5	Patch available	GHSA-677m-j7p3-52f9
—	socket.io-parser (npm)	3.4.0 to before 3.4.4	3.4.4	Patch available	GHSA-677m-j7p3-52f9
—	socket.io-parser (npm)	4.0.0 to before 4.2.6	4.2.6	Patch available	GHSA-677m-j7p3-52f9

socket.io Vendorsocketio Affected before 3.3.5; 3.4.0 to before 3.4.4; 4.0.0 to before 4.2.6 Fixed in 3.3.5, 3.4.4, 4.2.6 Patch available CNA
socket.io-parser (npm) Vendor— Affected before 3.3.5 Fixed in 3.3.5 Patch available GHSA-677m-j7p3-52f9
socket.io-parser (npm) Vendor— Affected 3.4.0 to before 3.4.4 Fixed in 3.4.4 Patch available GHSA-677m-j7p3-52f9
socket.io-parser (npm) Vendor— Affected 4.0.0 to before 4.2.6 Fixed in 4.2.6 Patch available GHSA-677m-j7p3-52f9

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:socket:socket.io-parser::::::node.js::*	before 3.3.5; 3.4.0 to before 3.4.4; 4.0.0 to before 4.2.6	Vulnerable	socketio

cpe:2.3:a:socket:socket.io-parser:*:*:*:*:*:node.js:*:* Versions before 3.3.5; 3.4.0 to before 3.4.4; 4.0.0 to before 4.2.6 Vulnerable ·socketio

Remediation

Fix · CNA socket.io (socketio) Fixed in 3.3.5, 3.4.4, 4.2.6
Fix · GHSA-677m-j7p3-52f9 socket.io-parser (npm) Fixed in 3.3.5 Advisory →
Fix · GHSA-677m-j7p3-52f9 socket.io-parser (npm) Fixed in 3.4.4 Advisory →
Fix · GHSA-677m-j7p3-52f9 socket.io-parser (npm) Fixed in 4.2.6 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Logging Subsystem for Red Hat OpenShift	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet: Fix deferred
Red Hat Fuse 7	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-33151
2026-10-03 Alias added: GHSA-677m-j7p3-52f9
2026-10-18 EPSS moved to the 50th–90th percentile
2026-10-25 EPSS moved to the below the 50th percentile

References

Patch 4

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-33151

Other 1

https://github.com/socketio/socket.io

TI-2022-02236 Socket.io - Improper type validation in attachment parsing CVSS 3.1CRITICAL 10.0
TI-2023-15971 Insufficient validation when decoding a Socket.IO packet CVSS 3.1HIGH 7.5
TI-2020-18428 socket.io-parser before 3.4.1 allows attackers to cause a denial of service (memory… CVSS 3.1HIGH 7.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences