Vulnerability Description
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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Socket | Engine.Io | >= 6.5.0, < 6.6.7 |
Related Weaknesses (CWE)
References
- https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c7Patch
- https://github.com/socketio/socket.io/releases/tag/[email protected]Release Notes
- https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3PatchVendor AdvisoryMitigation
FAQ
What is CVE-2026-59724?
CVE-2026-59724 is a vulnerability with a CVSS score of 7.5 (HIGH). 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_...
How severe is CVE-2026-59724?
CVE-2026-59724 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59724?
Check the references section above for vendor advisories and patch information. Affected products include: Socket Engine.Io.