High8.8Microsoft Server

High [CVE-2021-34525] Windows DNS Server Remote Code Execution Vulnerability

This high-severity Microsoft Server advisory covers CVE-2021-34525 affecting Windows Server 2012 R2 (Server Core installation), Windows Server 2016 (Server Core installation), Windows Server 2019 (Server Core installation).

CVE-2021-34525 Published Jul 14, 2021Updated by vendor Aug 10, 2026

CVE-2021-34525

Affected products & platforms

Microsoft ServerWindows Server

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Summary

Windows DNS Server Remote Code Execution Vulnerability

Affected products named by the advisory: Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); Windows Server 2016; Windows Server 2016 (Server Core installation); and 4 more.

Affected products named by the advisory: Windows Server 2019 (Server Core installation); Windows Server version 2004; Windows Server version 20H2.

Affected versions

Windows Server 2012 R2 6.3.9600.0 before 6.3.9600.20069
Windows Server 2012 R2 (Server Core installation) 6.3.9600.0 before 6.3.9600.20069
Windows Server 2016 10.0.14393.0 before 10.0.14393.4530
Windows Server 2016 (Server Core installation) 10.0.14393.0 before 10.0.14393.4530
Windows Server 2019 10.0.17763.0 before 10.0.17763.2061
Windows Server 2019 (Server Core installation) 10.0.17763.0 before 10.0.17763.2061
Windows Server version 2004 10.0.0 before 10.0.19041.1110
Windows Server version 20H2 10.0.0 before 10.0.19042.1110

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Fixed versions

6.3.9600.20069
10.0.14393.4530
10.0.17763.2061
10.0.19041.1110
10.0.19042.1110

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Mitigation

Upgrade to a fixed release: 6.3.9600.20069, 10.0.14393.4530, 10.0.17763.2061, 10.0.19041.1110, 10.0.19042.1110. That is the remediation for this advisory.

The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

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