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 attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/socketio/socket.io/commit/fc11285e14964c2132d122164bf130c355f60671	Patch
https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7	Release Notes
https://github.com/socketio/socket.io/security/advisories/GHSA-r635-g3xr-vw7x	Patch Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*

History

25 Oct 2026, 20:10

Type	Values Removed	Values Added
Summary		(es) Socket.IO permite comunicación bidireccional y de baja latencia para cada plataforma. Desde la versión 4.1.0 anterior a la 6.6.7, el transporte de sondeo del protocolo Engine.IO v4 no cierra correctamente la respuesta HTTP para solicitudes POST binarias no válidas con Content-Type: application/octet-stream, permitiendo a un atacante no autenticado agotar las conexiones y los sockets del lado del servidor. Este problema está solucionado en la versión 6.6.7.

Information

Published : 2026-07-08 16:16

Updated : 2026-10-25 20:10

NVD link : CVE-2026-59725

Mitre link : CVE-2026-59725

CVE.ORG link : CVE-2026-59725

JSON object : View

Products Affected

socket

engine.io

CWE

CWE-404

Improper Resource Shutdown or Release

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