CVE-2026-59724

Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enabled can resolve a crafted session ID such as __proto__ through an inherited property of the clients object during WebTransport upgrade handling, causing a TypeError and denial of service. This issue is fixed in version 6.6.7.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c	Patch
https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7	Release Notes
https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3	Patch Vendor Advisory Mitigation

Configurations

Configuration 1 (hide)

cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-07-08 16:16

Updated : 2026-07-13 15:08

NVD link : CVE-2026-59724

Mitre link : CVE-2026-59724

CVE.ORG link : CVE-2026-59724

JSON object : View

Products Affected

socket

engine.io

CWE

CWE-20

Improper Input Validation

NVD-CWE-noinfo

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