Skip to content
VulniPulse
Sign in
High7.5Microsoft Server

High [CVE-2021-26896] Windows DNS Server Denial of Service Vulnerability

This high-severity Microsoft Server advisory covers CVE-2021-26896 affecting Windows Server 2008 R2 Service Pack 1 (Server Core installation), Windows Server 2008 Service Pack 2 (Server Core installation), Windows Server 2012 (Server Core installation).

CVE-2021-26896 Published Mar 11, 2021Updated by vendor Aug 19, 2026
CVE-2021-26896
Affected products & platforms
Microsoft ServerWindows Server
Open vendor advisory

Android app · Google Play

Monitor future Microsoft Server CVEs from your phone.

Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.

Matching phone alertsOptional email delivery
Get CVE alertsSee app features

Summary

Windows DNS Server Denial of Service Vulnerability

Affected products named by the advisory: Windows Server 2008 R2 Service Pack 1; Windows Server 2008 R2 Service Pack 1 (Server Core installation); Windows Server 2008 Service Pack 2; Windows Server 2008 Service Pack 2 (Server Core installation); and 11 more.

Affected products named by the advisory: Windows Server 2012 (Server Core installation); Windows Server 2012 R2 (Server Core installation); Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); and 3 more.

Affected versions
  • Windows Server 2008 R2 Service Pack 1 6.1.7601.0 before 6.1.7601.24566
  • Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.0 before 6.1.7601.24566
  • Windows Server 2008 Service Pack 2 6.0.6003.0 before 6.0.6003.21070
  • Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.0 before 6.0.6003.21070
  • Windows Server 2012 6.2.9200.0 before 6.2.9200.23298
  • Windows Server 2012 (Server Core installation) 6.2.9200.0 before 6.2.9200.23298
  • Windows Server 2012 R2 6.3.9600.0 before 6.3.9600.19968
  • Windows Server 2012 R2 (Server Core installation) 6.3.9600.0 before 6.3.9600.19968
  • Windows Server 2016 10.0.14393.0 before 10.0.14393.4283
  • Windows Server 2016 (Server Core installation) 10.0.14393.0 before 10.0.14393.4283
  • Windows Server 2019 10.0.17763.0 before 10.0.17763.1817
  • Windows Server 2019 (Server Core installation) 10.0.17763.0 before 10.0.17763.1817

Official advisory · high-confidence parse· fetched 1 hour ago·verify at source

Fixed versions
  • 6.1.7601.24566
  • 6.0.6003.21070
  • 6.2.9200.23298
  • 6.3.9600.19968
  • 10.0.14393.4283
  • 10.0.17763.1817
  • 10.0.19043.867
  • 10.0.18363.1440

Official advisory · high-confidence parse· fetched 1 hour ago·verify at source

Mitigation

Upgrade to a fixed release: 6.1.7601.24566, 6.0.6003.21070, 6.2.9200.23298, 6.3.9600.19968, 10.0.14393.4283, 10.0.17763.1817. 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 1 hour ago·verify at source

Discussion(0)

No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.

Sign in to join the discussion.