What’s Vulnerable › Vulnerabilities

CVE-2020-0836: Windows DNS Denial of Service Vulnerability

• Severity: medium (CVSS 5.0 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-11 · updated 2026-06-17

Description

<p>A denial of service vulnerability exists in Windows DNS when it fails to properly handle queries. An attacker who successfully exploited this vulnerability could cause the DNS service to become nonresponsive.</p> <p>To exploit the vulnerability, an authenticated attacker could send malicious DNS queries to a target, resulting in a denial of service.</p> <p>The update addresses the vulnerability by correcting how Windows DNS processes queries.</p>

Affected products

• Microsoft Windows Server 2008: all versions
• Microsoft Windows Server 2012: r2
• Microsoft Windows Server 2016: 1903, 1909, 2004
• Microsoft Windows Server 2019: all versions
• 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 Server 2008 R2 Service Pack 1 publication; Microsoft Windows Server 2008 Service Pack 2 publication; Microsoft Windows Server 2012 publication; Microsoft Windows Server 2012 R2 publication; Microsoft Windows Server 2016 publication; Microsoft Windows Server 2019 publication; Microsoft Windows Server, version 1903 (Server Core installation) publication; Microsoft Windows Server, version 1909 (Server Core installation) publication; Microsoft Windows Server version 2004 publication. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0836
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0836

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