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CVE-2020-16891: Windows Hyper-V Remote Code Execution Vulnerability

• Severity: high (CVSS 7.2 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-10-16 · updated 2026-06-17
• Weakness: CWE-20

Description

<p>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.</p> <p>An attacker who successfully exploited the vulnerability could execute arbitrary code on the host operating system.</p> <p>The security update addresses the vulnerability by correcting how Hyper-V validates guest operating system user input.</p>

Affected products

• Microsoft Windows 10 Version 1607: 1607, 1709, 1803, 1809, 1903, 1909 (+1)
• Microsoft Windows 7: all versions
• Microsoft Windows 8.1: all versions
• Microsoft Windows Server 2008: r2-sp1
• Microsoft Windows Server 2012: r2
• Microsoft Windows Server 2016: 1903, 1909, 2004
• Microsoft Windows Server 2019: all versions
• Microsoft Windows 10 Version 1507: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1607: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1709: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1803: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for x64-based Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1909: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 2004: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 7 Service Pack 1: from 6.1.0 before publication — fixed in publication
• Microsoft Windows 8.1: from 6.3.0 before publication — fixed in publication
• Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.0 before publication — fixed in publication
• Microsoft Windows Server 2008 Service Pack 2: from 6.0.0 before publication — fixed in publication
• Microsoft Windows Server 2012: from 6.2.0 before publication — fixed in publication
• Microsoft Windows Server 2012 R2: from 6.3.0 before publication — fixed in publication
• Microsoft Windows Server 2016: from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server 2019: from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1903 (Server Core installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1909 (Server Core installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server version 2004: from 10.0.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 publication; Microsoft Windows 10 1607 publication; Microsoft Windows 10 1709 publication; Microsoft Windows 10 1803 publication; Microsoft Windows 10 publication; Microsoft Windows 10 Version 1903 for x64-based Systems publication; Microsoft Windows 10 1909 publication; Microsoft Windows 10 2004 publication; Microsoft Windows 7 Service Pack 1 publication; Microsoft Windows 8.1 publication; Microsoft Windows Server 2008 R2 Service Pack 1 publication; Microsoft Windows Server 2008 Service Pack 2 publication. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16891
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16891

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