socket.io: engine.io: Socket.IO: Denial of Service via invalid binary POST requests

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

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...