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TI-2026-16841 Aliases CVE-2026-20810GHSA-c77x-pfg5-gxc3

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Priority LOW 37CWE-590Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Privilege escalation
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

Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00489 42nd percentileScored 2026-11-07
Fix Fixed Microsoft: 2 updates

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftWindows 10 Version 180910.0.17763.0 to before 10.0.17763.827610.0.17763.8276Patch availableCNA
MicrosoftWindows 10 Version 21H210.0.19044.0 to before 10.0.19044.680910.0.19044.6809Patch availableCNA
MicrosoftWindows 10 Version 22H210.0.19045.0 to before 10.0.19045.680910.0.19045.6809Patch availableCNA
MicrosoftWindows Server 201910.0.17763.0 to before 10.0.17763.827610.0.17763.8276Patch availableCNA
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 to before 10.0.17763.827610.0.17763.8276Patch availableCNA
  • Windows 10 Version 1809 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8276 Fixed in 10.0.17763.8276 Patch available CNA
  • Windows 10 Version 21H2 VendorMicrosoft Affected 10.0.19044.0 to before 10.0.19044.6809 Fixed in 10.0.19044.6809 Patch available CNA
  • Windows 10 Version 22H2 VendorMicrosoft Affected 10.0.19045.0 to before 10.0.19045.6809 Fixed in 10.0.19045.6809 Patch available CNA
  • Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8276 Fixed in 10.0.17763.8276 Patch available CNA
  • Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8276 Fixed in 10.0.17763.8276 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*before 10.0.17763.8276VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*before 10.0.17763.8276VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*before 10.0.19044.6809VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*before 10.0.19045.6809VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*before 10.0.17763.8276VulnerableMicrosoft
  • cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* Versions before 10.0.17763.8276 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* Versions before 10.0.17763.8276 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:* Versions before 10.0.19044.6809 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:* Versions before 10.0.19045.6809 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* Versions before 10.0.17763.8276 Vulnerable ·Microsoft

Remediation

Microsoft 2 updates

  • KB5073724
    Security Update
    • Windows 10 Version 21H2 for 32-bit Systems 10.0.19044.6809
    • Windows 10 Version 21H2 for ARM64-based Systems 10.0.19044.6809
    • Windows 10 Version 21H2 for x64-based Systems 10.0.19044.6809
    • Windows 10 Version 22H2 for 32-bit Systems 10.0.19045.6809
    • Windows 10 Version 22H2 for ARM64-based Systems 10.0.19045.6809
    • Windows 10 Version 22H2 for x64-based Systems 10.0.19045.6809
  • KB5073723
    Security Update
    • Windows 10 Version 1809 for 32-bit Systems 10.0.17763.8276
    • Windows 10 Version 1809 for x64-based Systems 10.0.17763.8276
    • Windows Server 2019 10.0.17763.8276
    • Windows Server 2019 (Server Core installation) 10.0.17763.8276

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Elevation of Privilege
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Less Likely

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-20810
  2. 2026-10-03 Alias added: GHSA-c77x-pfg5-gxc3

References

Patch 1

  • TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-73128 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2026-17367 MSHTML Framework Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2026-17364 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2025-24062 Windows SMB Client Elevation of Privilege Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2025-24042 Internet Shortcut Files Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
See all 4016 →

Sources

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