CVE-2020-1243: Microsoft Windows 10

High severity, CVSS 7.8. EPSS: 0.9% chance of exploitation in the next 30 days.

<p>A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate specific malicious data from a user on a guest operating system.</p> <p>To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application.</p> <p>The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.</p>

Affected products

• Microsoft Windows 10: version 1607 only; version 1709 only; version 1803 only; version 1809 only; version 1903 only; version 2004 only
• Microsoft Windows Server 2016: affected versions not specified; version 1903 only; version 1909 only; version 2004 only
• Microsoft Windows Server 2019: affected versions not specified

Published 2020-10-16. Last modified 2026-06-17.