CVE-2026-83657: Windows Modern Device Management (MDM) Tampering Vulnerability

Overview

Severity

Medium (CVSS 5.5)

CVSS Vector

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

Category

Tampering

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Oct

Released

2026-10-13

Description

Weak authentication in Windows Modern Device Management (MDM) allows an authorized attacker to perform tampering locally.

Affected Products (4)

Windows

• Windows 10 Version 1809 for 32-bit Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows Server 2019
• Windows Server 2019 (Server Core installation)

Security Updates (1)

• 5126651

Acknowledgments

haowei yan & xiaozun tang

Revision History

• 2026-10-13: Information published.