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Fencer Vulns
high 8.8

CVE-2020-16891 json

Windows Hyper-V Remote Code Execution Vulnerability

published 2020-10-16 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-8849

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

<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>

Patch / fix

Exploit prediction

0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • Microsoft Windows 10 Version 2004
  • Microsoft Windows Server version 2004
  • Microsoft Windows 10 Version 1803
  • Microsoft Windows 10 Version 1809
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2019 (Server Core installation)
  • Microsoft Windows 10 Version 1909
  • Microsoft Windows Server, version 1909 (Server Core installation)
  • Microsoft Windows 10 Version 1709
  • Microsoft Windows 10 Version 1903 for x64-based Systems
  • Microsoft Windows Server, version 1903 (Server Core installation)
  • Microsoft Windows 10 Version 1507
  • Microsoft Windows 10 Version 1607
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2016 (Server Core installation)
  • Microsoft Windows 7 Service Pack 1
  • Microsoft Windows 8.1
  • Microsoft Windows Server 2008 Service Pack 2
  • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation)
  • Microsoft Windows Server 2008 R2 Service Pack 1
  • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)
  • Microsoft Windows Server 2012
  • Microsoft Windows Server 2012 (Server Core installation)
  • Microsoft Windows Server 2012 R2
  • Microsoft Windows Server 2012 R2 (Server Core installation)

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.