CVE-2026-59725 HIGH

CVE-2026-59725: Socket.IO: Engine.IO Polling Transport Connection Exhaustion

Vendor Socketio
Product socket.io
Weakness CWE-404
Published July 8, 2026
Last update July 8, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 8, 2026 CVE published
July 8, 2026 Record updated