high7.5
CVE-2026-59725
Socket.IO enables bidirectional and low-latency communication for every platform.
Impact
Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport does not properly close the HTTP response for invalid binary POST requests with Content-Type: application/octet-stream, allowing an unauthenticated attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | engine.io | >= 4.1.0, < 6.6.7 | 6.6.7 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Socket | Engine.Io | from 4.1.0 before 6.6.7 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-r635-g3xr-vw7x
- https://github.com/socketio/socket.io/security/advisories/GHSA-r635-g3xr-vw7x
- https://nvd.nist.gov/vuln/detail/CVE-2026-59725
- https://github.com/socketio/socket.io/commit/fc11285e14964c2132d122164bf130c355f60671
- https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7