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TI-2021-13526 Aliases CVE-2021-34499GHSA-6g4v-wpgv-gp6c

Windows DNS Server Denial of Service Vulnerability

Priority LOW 34Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · 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 Denial of Service Vulnerability

Why it matters now

EPSS 0.02869 86th percentileScored 2026-11-07
Fix Fixed Microsoft: 11 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 6.1.7601.256616.1.7601.25661Patch availableCNA
MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)6.1.7601.0 to before 6.1.7601.256616.1.7601.25661Patch availableCNA
MicrosoftWindows Server 2008 Service Pack 26.0.6003.0 to before 6.0.6003.211676.0.6003.21167Patch availableCNA
MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)6.0.6003.0 to before 6.0.6003.211676.0.6003.21167Patch availableCNA
MicrosoftWindows Server 20126.2.9200.0 to before 6.2.9200.234096.2.9200.23409Patch availableCNA
MicrosoftWindows Server 2012 (Server Core installation)6.2.9200.0 to before 6.2.9200.234096.2.9200.23409Patch availableCNA
MicrosoftWindows Server 2012 R26.3.9600.0 to before 6.3.9600.200696.3.9600.20069Patch availableCNA
MicrosoftWindows Server 2012 R2 (Server Core installation)6.3.9600.0 to before 6.3.9600.200696.3.9600.20069Patch availableCNA
MicrosoftWindows Server 201610.0.14393.0 to before 10.0.14393.453010.0.14393.4530Patch availableCNA
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 to before 10.0.14393.453010.0.14393.4530Patch availableCNA
MicrosoftWindows Server 201910.0.17763.0 to before 10.0.17763.206110.0.17763.2061Patch availableCNA
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 to before 10.0.17763.206110.0.17763.2061Patch availableCNA
MicrosoftWindows Server version 200410.0.0 to before 10.0.19041.111010.0.19041.1110Patch availableCNA
MicrosoftWindows Server version 20H210.0.0 to before 10.0.19042.111010.0.19042.1110Patch availableCNA
  • Windows Server 2008 R2 Service Pack 1 VendorMicrosoft Affected 6.1.7601.0 to before 6.1.7601.25661 Fixed in 6.1.7601.25661 Patch available CNA
  • Windows Server 2008 R2 Service Pack 1 (Server Core installation) VendorMicrosoft Affected 6.1.7601.0 to before 6.1.7601.25661 Fixed in 6.1.7601.25661 Patch available CNA
  • Windows Server 2008 Service Pack 2 VendorMicrosoft Affected 6.0.6003.0 to before 6.0.6003.21167 Fixed in 6.0.6003.21167 Patch available CNA
  • Windows Server 2008 Service Pack 2 (Server Core installation) VendorMicrosoft Affected 6.0.6003.0 to before 6.0.6003.21167 Fixed in 6.0.6003.21167 Patch available CNA
  • Windows Server 2012 VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.23409 Fixed in 6.2.9200.23409 Patch available CNA
  • Windows Server 2012 (Server Core installation) VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.23409 Fixed in 6.2.9200.23409 Patch available CNA
  • Windows Server 2012 R2 VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.20069 Fixed in 6.3.9600.20069 Patch available CNA
  • Windows Server 2012 R2 (Server Core installation) VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.20069 Fixed in 6.3.9600.20069 Patch available CNA
  • Windows Server 2016 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.4530 Fixed in 10.0.14393.4530 Patch available CNA
  • Windows Server 2016 (Server Core installation) VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.4530 Fixed in 10.0.14393.4530 Patch available CNA
  • Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.2061 Fixed in 10.0.17763.2061 Patch available CNA
  • Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.2061 Fixed in 10.0.17763.2061 Patch available CNA
  • Windows Server version 2004 VendorMicrosoft Affected 10.0.0 to before 10.0.19041.1110 Fixed in 10.0.19041.1110 Patch available CNA
  • Windows Server version 20H2 VendorMicrosoft Affected 10.0.0 to before 10.0.19042.1110 Fixed in 10.0.19042.1110 Patch available CNA

CPE configurations NVD · 8

CPEVersionsRoleVendor
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*not specified by NVDVulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*r2 sp1VulnerableMicrosoft
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_2016:2004:*:*:*:*:*:*:*2004VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*not specified by NVDVulnerableMicrosoft
  • cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:* Versions r2 sp1 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_2016:2004:*:*:*:*:*:*:* Versions 2004 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft

Remediation

Microsoft 11 updates

  • KB5004307
    Security Only
    • Windows 7 for 32-bit Systems Service Pack 1 6.1.7601.25661
    • Windows 7 for x64-based Systems Service Pack 1 6.1.7601.25661
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 6.1.7601.25661
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 6.1.7601.25661
  • KB5004305
    Monthly Rollup
    • Windows Server 2008 for 32-bit Systems Service Pack 2 6.0.6003.21167
    • Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 6.0.6003.21167
    • Windows Server 2008 for x64-based Systems Service Pack 2 6.0.6003.21167
    • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 6.0.6003.21167
  • KB5004302
    Security Only
    • Windows Server 2012 6.2.9200.23409
    • Windows Server 2012 (Server Core installation) 6.2.9200.23409
Show 8 more Microsoft updates
  • KB5004299
    Security Only
    • Windows Server 2008 for 32-bit Systems Service Pack 2 6.0.6003.21167
    • Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 6.0.6003.21167
    • Windows Server 2008 for x64-based Systems Service Pack 2 6.0.6003.21167
    • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 6.0.6003.21167
  • KB5004298
    Monthly Rollup
    • Windows 8.1 for 32-bit systems 6.3.9600.20069
    • Windows 8.1 for x64-based systems 6.3.9600.20069
    • Windows RT 8.1 6.3.9600.20069
    • Windows Server 2012 R2 6.3.9600.20069
    • Windows Server 2012 R2 (Server Core installation) 6.3.9600.20069
  • KB5004294
    Monthly Rollup
    • Windows Server 2012 6.2.9200.23409
    • Windows Server 2012 (Server Core installation) 6.2.9200.23409
  • KB5004289
    Monthly Rollup
    • Windows 7 for 32-bit Systems Service Pack 1 6.1.7601.25661
    • Windows 7 for x64-based Systems Service Pack 1 6.1.7601.25661
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 6.1.7601.25661
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 6.1.7601.25661
  • KB5004285
    Security Only
    • Windows 8.1 for 32-bit systems 6.3.9600.20069
    • Windows 8.1 for x64-based systems 6.3.9600.20069
    • Windows Server 2012 R2 6.3.9600.20069
    • Windows Server 2012 R2 (Server Core installation) 6.3.9600.20069
  • KB5004244
    Security Update
    • Windows 10 Version 1809 for 32-bit Systems 10.0.17763.2061
    • Windows 10 Version 1809 for ARM64-based Systems 10.0.17763.2061
    • Windows 10 Version 1809 for x64-based Systems 10.0.17763.2061
    • Windows Server 2019 10.0.17763.2061
    • Windows Server 2019 (Server Core installation) 10.0.17763.2061
  • KB5004238
    Security Update
    • Windows 10 Version 1607 for 32-bit Systems 10.0.14393.4530
    • Windows 10 Version 1607 for x64-based Systems 10.0.14393.4530
    • Windows Server 2016 10.0.14393.4530
    • Windows Server 2016 (Server Core installation) 10.0.14393.4530
  • KB5004237
    Security Update
    • Windows 10 Version 2004 for 32-bit Systems 10.0.19041.1110
    • Windows 10 Version 2004 for ARM64-based Systems 10.0.19041.1110
    • Windows 10 Version 2004 for x64-based Systems 10.0.19041.1110
    • Windows 10 Version 20H2 for 32-bit Systems 10.0.19042.1110
    • Windows 10 Version 20H2 for ARM64-based Systems 10.0.19042.1110
    • Windows 10 Version 21H1 for 32-bit Systems 10.0.19043.1110
    • Windows 10 Version 21H1 for ARM64-based Systems 10.0.19043.1110
    • Windows 10 Version 21H1 for x64-based Systems 10.0.19043.1110
    • Windows Server, version 2004 (Server Core installation) 10.0.19041.1110
    • Windows Server, version 20H2 (Server Core Installation) 10.0.19042.1110

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Denial of Service
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Less Likely

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-34499
  2. 2026-10-03 Alias added: GHSA-6g4v-wpgv-gp6c

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