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TI-2021-08502 Aliases CVE-2021-26895GHSA-wjv8-g83f-g23g

Windows DNS Server Remote Code Execution Vulnerability

Priority MEDIUM 53Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.

Summary

Windows DNS Server Remote Code Execution Vulnerability

Why it matters now

EPSS 0.07755 94th percentileScored 2026-11-07
Fix Fixed Microsoft: 12 updates

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftWindows Server 2008 R2 Service Pack 16.1.7601.0 to before 6.1.7601.245666.1.7601.24566Patch availableCNA
MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)6.1.7601.0 to before 6.1.7601.245666.1.7601.24566Patch availableCNA
MicrosoftWindows Server 2008 Service Pack 26.0.6003.0 to before 6.0.6003.210706.0.6003.21070Patch availableCNA
MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)6.0.6003.0 to before 6.0.6003.210706.0.6003.21070Patch availableCNA
MicrosoftWindows Server 20126.2.9200.0 to before 6.2.9200.232986.2.9200.23298Patch availableCNA
MicrosoftWindows Server 2012 (Server Core installation)6.2.9200.0 to before 6.2.9200.232986.2.9200.23298Patch availableCNA
MicrosoftWindows Server 2012 R26.3.9600.0 to before 6.3.9600.199686.3.9600.19968Patch availableCNA
MicrosoftWindows Server 2012 R2 (Server Core installation)6.3.9600.0 to before 6.3.9600.199686.3.9600.19968Patch availableCNA
MicrosoftWindows Server 201610.0.14393.0 to before 10.0.14393.428310.0.14393.4283Patch availableCNA
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 to before 10.0.14393.428310.0.14393.4283Patch availableCNA
MicrosoftWindows Server 201910.0.17763.0 to before 10.0.17763.181710.0.17763.1817Patch availableCNA
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 to before 10.0.17763.181710.0.17763.1817Patch availableCNA
MicrosoftWindows Server version 200410.0.0 to before 10.0.19043.86710.0.19043.867Patch availableCNA
MicrosoftWindows Server version 20H210.0.0 to before 10.0.19043.86710.0.19043.867Patch availableCNA
MicrosoftWindows Server, version 1909 (Server Core installation)10.0.0 to before 10.0.18363.144010.0.18363.1440Patch availableCNA
  • Windows Server 2008 R2 Service Pack 1 VendorMicrosoft Affected 6.1.7601.0 to before 6.1.7601.24566 Fixed in 6.1.7601.24566 Patch available CNA
  • Windows Server 2008 R2 Service Pack 1 (Server Core installation) VendorMicrosoft Affected 6.1.7601.0 to before 6.1.7601.24566 Fixed in 6.1.7601.24566 Patch available CNA
  • Windows Server 2008 Service Pack 2 VendorMicrosoft Affected 6.0.6003.0 to before 6.0.6003.21070 Fixed in 6.0.6003.21070 Patch available CNA
  • Windows Server 2008 Service Pack 2 (Server Core installation) VendorMicrosoft Affected 6.0.6003.0 to before 6.0.6003.21070 Fixed in 6.0.6003.21070 Patch available CNA
  • Windows Server 2012 VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.23298 Fixed in 6.2.9200.23298 Patch available CNA
  • Windows Server 2012 (Server Core installation) VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.23298 Fixed in 6.2.9200.23298 Patch available CNA
  • Windows Server 2012 R2 VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.19968 Fixed in 6.3.9600.19968 Patch available CNA
  • Windows Server 2012 R2 (Server Core installation) VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.19968 Fixed in 6.3.9600.19968 Patch available CNA
  • Windows Server 2016 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.4283 Fixed in 10.0.14393.4283 Patch available CNA
  • Windows Server 2016 (Server Core installation) VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.4283 Fixed in 10.0.14393.4283 Patch available CNA
  • Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.1817 Fixed in 10.0.17763.1817 Patch available CNA
  • Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.1817 Fixed in 10.0.17763.1817 Patch available CNA
  • Windows Server version 2004 VendorMicrosoft Affected 10.0.0 to before 10.0.19043.867 Fixed in 10.0.19043.867 Patch available CNA
  • Windows Server version 20H2 VendorMicrosoft Affected 10.0.0 to before 10.0.19043.867 Fixed in 10.0.19043.867 Patch available CNA
  • Windows Server, version 1909 (Server Core installation) VendorMicrosoft Affected 10.0.0 to before 10.0.18363.1440 Fixed in 10.0.18363.1440 Patch available CNA

CPE configurations NVD · 10

CPEVersionsRoleVendor
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*r2 sp1VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:x64:*sp2VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:x86:*sp2VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*not specified by NVDVulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:-:*:-:*r2VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*not specified by NVDVulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*20h2VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*1909VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*2004VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*not specified by NVDVulnerableMicrosoft
  • cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:* Versions r2 sp1 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:x64:* Versions sp2 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:x86:* Versions sp2 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:-:*:-:* Versions r2 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:* Versions 20h2 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:* Versions 1909 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:* Versions 2004 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft

Remediation

Microsoft 12 updates

  • KB5000856
    https
    • Windows Server 2008 for 32-bit Systems Service Pack 2 Security Only
    • Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) Security Only
    • Windows Server 2008 for x64-based Systems Service Pack 2 Security Only
    • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) Security Only
  • KB5000853
    https
    • Windows 8.1 for 32-bit systems Security Only
    • Windows 8.1 for x64-based systems Security Only
    • Windows Server 2012 R2 Security Only
    • Windows Server 2012 R2 (Server Core installation) Security Only
  • KB5000851
    https
    • Windows 7 for 32-bit Systems Service Pack 1 Security Only
    • Windows 7 for x64-based Systems Service Pack 1 Security Only
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 Security Only
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) Security Only
Show 9 more Microsoft updates
  • KB5000848
    Monthly Rollup
    • Internet Explorer 11 6.3.9600.19968
    • Windows 8.1 for 32-bit systems 6.3.9600.19968
    • Windows 8.1 for x64-based systems 6.3.9600.19968
    • Windows RT 8.1 6.3.9600.19968
    • Windows Server 2012 R2 6.3.9600.19968
    • Windows Server 2012 R2 (Server Core installation) 6.3.9600.19968
  • KB5000847
    Monthly Rollup
    • Internet Explorer 11 6.2.9200.23298
    • Windows Server 2012 6.2.9200.23298
    • Windows Server 2012 (Server Core installation) 6.2.9200.23298
  • KB5000844
    Monthly Rollup
    • Internet Explorer 9 6.0.6003.21070
    • Windows Server 2008 for 32-bit Systems Service Pack 2 6.0.6003.21070
    • Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 6.0.6003.21070
    • Windows Server 2008 for x64-based Systems Service Pack 2 6.0.6003.21070
    • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 6.0.6003.21070
  • KB5000841
    Monthly Rollup
    • Internet Explorer 11 6.1.7601.24566
    • Windows 7 for 32-bit Systems Service Pack 1 6.1.7601.24566
    • Windows 7 for x64-based Systems Service Pack 1 6.1.7601.24566
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 6.1.7601.24566
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 6.1.7601.24566
  • KB5000840
    https
    • Windows Server 2012 Security Only
    • Windows Server 2012 (Server Core installation) Security Only
  • KB5000822
    Security Update
    • Internet Explorer 11 10.0.17763.1817
    • Microsoft Edge (EdgeHTML-based) 10.0.17763.1817
    • Windows 10 Version 1809 for 32-bit Systems 10.0.17763.1817
    • Windows 10 Version 1809 for ARM64-based Systems 10.0.17763.1817
    • Windows 10 Version 1809 for x64-based Systems 10.0.17763.1817
    • Windows Server 2019 10.0.17763.1817
    • Windows Server 2019 (Server Core installation) 10.0.17763.1817
  • KB5000808
    Security Update
    • Internet Explorer 11 10.0.18363.1440
    • Microsoft Edge (EdgeHTML-based) 10.0.18363.1440
    • Windows 10 Version 1909 for 32-bit Systems 10.0.18363.1440
    • Windows 10 Version 1909 for ARM64-based Systems 10.0.18363.1440
    • Windows 10 Version 1909 for x64-based Systems 10.0.18363.1440
    • Windows Server, version 1909 (Server Core installation) 10.0.18363.1440
  • KB5000803
    Security Update
    • Internet Explorer 11 10.0.14393.4283
    • Microsoft Edge (EdgeHTML-based) 10.0.14393.4283
    • Windows 10 Version 1607 for 32-bit Systems 10.0.14393.4283
    • Windows 10 Version 1607 for x64-based Systems 10.0.14393.4283
    • Windows Server 2016 10.0.14393.4283
    • Windows Server 2016 (Server Core installation) 10.0.14393.4283
  • KB5000802
    Security Update
    • Internet Explorer 11 10.0.19043.867
    • Microsoft Edge (EdgeHTML-based) 10.0.19043.867
    • Windows 10 Version 2004 for 32-bit Systems 10.0.19043.867
    • Windows 10 Version 2004 for ARM64-based Systems 10.0.19043.867
    • Windows 10 Version 2004 for x64-based Systems 10.0.19043.867
    • Windows 10 Version 20H2 for 32-bit Systems 10.0.19043.867
    • Windows 10 Version 20H2 for ARM64-based Systems 10.0.19043.867
    • Windows Server, version 2004 (Server Core installation) 10.0.19043.867
    • Windows Server, version 20H2 (Server Core Installation) 10.0.19043.867

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Remote Code Execution
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Less Likely

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-26895
  2. 2026-10-03 Alias added: GHSA-wjv8-g83f-g23g

References

Patch 2

  • TI-2020-01431 Netlogon Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 10.0
  • TI-2020-01310 Improper input validation in Microsoft Windows Server KEVCVSS 3.1CRITICAL 10.0
  • TI-2019-00485 Use after free in Microsoft Windows KEVCVSS 3.1CRITICAL 9.8
  • TI-2017-06077 Microsoft Windows XP SP3, Windows XP x64 XP2, Windows Server 2003 SP2, Windows Vista… KEVCVSS 3.1CRITICAL 9.8
  • TI-2015-01465 HTTP.sys in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8, Windows 8.1… KEVCVSS 3.1CRITICAL 9.8
  • TI-2008-04072 The Server service in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and… KEVCVSS 3.1CRITICAL 9.8
See all 3551 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences