PT-2026-56488 · Socket.Io · Socket.Io

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CVE-2026-59725

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Published

2026-07-08

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Updated

2026-08-18

CVSS v3.1

7.5

High

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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. This behavior allows an unauthenticated attacker to exhaust server-side connections and sockets, potentially leading to a denial of service.
Recommendations Update to version 6.6.7.

Exploit

Fix

DoS

Improper Resource Release

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Weakness Enumeration

Related Identifiers

CVE-2026-59725
GHSA-R635-G3XR-VW7X
RHSA-2026:42986

Affected Products

Socket.Io