CVE-2026-59725 — Socket.IO: Engine.IO Polling Transport Connection Exhaustion
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 HT…
Published: 2026-07-08 · CVSS: 7.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7