Socket.IO enables bidirectional and low-latency communication for every platform.

Code

The project this record applies to. Exploit listings stay in References.

• Repository · github.com

Timeline

Detection, updates, and resolution for this record.

1. Jul 8, 2026 · NIST NVD

   Detected

   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.

2. Oct 14, 2026 · NIST NVD

   Updated

   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

• cpe socket/engine.ioversion unspecified

Sources

• CVE.orgVulnerability recordCVE-2026-59725

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-59725

  30-day exploitation probability 0.6%

  first.org
• NIST NVDVulnerability recordCVE-2026-59725

  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 u

  nvd.nist.gov

References

• Patch · github.com
• Release Notes · github.com
• Patch · github.com