CVE-2026-59725

A flaw was found in Socket.IO, specifically within the Engine.IO protocol v4 polling transport. An unauthenticated attacker can exploit this vulnerability by sending invalid binary POST requests with a Content-Type of application/octet-stream. This improper handling of requests prevents the HTTP...

CVE-2026-59725: Improper Resource Shutdown or Release

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...

PT-2026-56488

Name of the Vulnerable Software and Affected Versions Socket.IO versions 4.1.0 through 6.6.6 Description The Engine.IO protocol v4 polling transport fails to properly close the HTTP response when receiving invalid binary POST requests that use the Content-Type: application/octet-stream header. Th...