CVE-2026-59724

socketio socket.ioVulnerabilityCVSS 7.5

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.

No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.

Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.

CVE-2026-59724 socketio socket.io Vulnerability

Severity metrics

CVSS 3.1 : 7.5 HIGH

Attack vectorNetwork (remote)

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

Confidentiality impactNone

Integrity impactNone

Availability impactHigh

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

Affected & fixed versions by distribution

Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.

No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.

Sources

Advisory NVD CVE.org

Published 2026-07-08 · updated 2026-07-27 · source: NVD