PT-2026-56487 · Socket.Io · Socket.Io

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-59724

NVD

CVSS v3.1

7.5

High

Base vector

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

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.

Fix

RCE

Weakness Enumeration

CWE-20

Related Identifiers

CVE-2026-59724

Affected Products

Socket.Io

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-59724 · Security Note
• https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3 · Note
• https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c · Note
• https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7 · Note