high7.5
CVE-2026-59724
Socket.IO enables bidirectional and low-latency communication for every platform.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | engine.io | >= 6.5.0, < 6.6.7 | 6.6.7 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Socket | Engine.Io | from 6.5.0 before 6.6.7 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-gr94-w7qr-f4j3
- https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3
- https://nvd.nist.gov/vuln/detail/CVE-2026-59724
- https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c
- https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7