CVE-2020-16891: Microsoft Windows 10

High severity, CVSS 8.8. EPSS: 0.9% chance of exploitation in the next 30 days.

A remote code execution vulnerability exists when Windows Hyper-V on a host server fails to properly validate input from an authenticated user on a guest operating system. To exploit the vulnerability, an attacker could run a specially crafted application on a guest operating system that could cause the Hyper-V host operating system to execute arbitrary code. An attacker who successfully exploited the vulnerability could execute arbitrary code on the host operating system. The security update addresses the vulnerability by correcting how Hyper-V validates guest operating system user input.

Affected products

Microsoft Windows 10: affected versions not specified; version 1607 only; version 1709 only; version 1803 only; version 1809 only; version 1903 only; …
Microsoft Windows 7: affected versions not specified
Microsoft Windows 8.1: affected versions not specified
Microsoft Windows Server 2008: affected versions not specified; version r2 only
Microsoft Windows Server 2012: affected versions not specified; version r2 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.