---
id: CVE-2020-0909
title: >-
  A denial of service vulnerability exists when Hyper-V on a Windows Server
  fails to properly handle specially crafted network packets.

  To exploit the vulnerability, an attacker would send specially crafted network
  packets to the Hyper-V S…
summary: >-
  A denial of service vulnerability exists when Hyper-V on a Windows Server
  fails to properly handle specially crafted network packets.

  To exploit the vulnerability, an attacker would send specially crafted network
  packets to the Hyper-V S…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: microsoft
product: windows_10
affected:
  - windows_10
  - windows_10 = 1607
  - windows_10 = 1709
  - windows_10 = 1803
  - windows_10 = 1809
  - windows_10 = 1903
  - windows_10 = 1909
  - windows_7
  - windows_8.1
  - windows_server_2008
  - windows_server_2008 = r2
  - windows_server_2012
  - windows_server_2012 = r2
  - windows_server_2016
  - windows_server_2016 = 1803
  - windows_server_2016 = 1903
  - windows_server_2016 = 1909
  - windows_server_2019
published: '2020-05-21'
updated: '2026-08-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-0909'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-0909'
    label: secure@microsoft.com
  - url: >-
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0909
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.04577
epssPercentile: 0.91219
ingestedAt: '2026-08-19T17:42:35.989Z'
---

## Overview

A denial of service vulnerability exists when Hyper-V on a Windows Server fails to properly handle specially crafted network packets.
To exploit the vulnerability, an attacker would send specially crafted network packets to the Hyper-V Server.
The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to properly handle these network packets.

## Affected

- `windows_10`
- `windows_10 = 1607`
- `windows_10 = 1709`
- `windows_10 = 1803`
- `windows_10 = 1809`
- `windows_10 = 1903`
- `windows_10 = 1909`
- `windows_7`
- `windows_8.1`
- `windows_server_2008`
- `windows_server_2008 = r2`
- `windows_server_2012`
- `windows_server_2012 = r2`
- `windows_server_2016`
- `windows_server_2016 = 1803`
- `windows_server_2016 = 1903`
- `windows_server_2016 = 1909`
- `windows_server_2019`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.