Review reviewHigh

CVE-2026-33099

Microsoft Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2

Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

PRIORITY ASSESSMENT

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.18%

Technical severityCVSS 7

Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Product: Microsoft Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2
Affected versions: >= 10.0.14393.0 < 10.0.14393.9060, >= 10.0.17763.0 < 10.0.17763.8644, >= 10.0.19044.0 < 10.0.19044.7184, >= 10.0.19045.0 < 10.0.19045.7184, >= 10.0.22631.0 < 10.0.22631.6936, >= 10.0.26100.0 < 10.0.26100.8246, >= 10.0.26200.0 < 10.0.26200.8246, >= 6.2.9200.0 < 6.2.9200.26026, >= 6.3.9600.0 < 6.3.9600.23132, >= 10.0.20348.0 < 10.0.20348.5020, >= 10.0.25398.0 < 10.0.25398.2274, < 10.0.14393.9060, < 10.0.17763.8644, < 10.0.19044.7184, < 10.0.19045.7184, < 10.0.22631.6936, < 10.0.26100.8246, < 10.0.26200.8246, r2, < 10.0.20348.5020
Fixed versions: 10.0.14393.9060, 10.0.17763.8644, 10.0.19044.7184, 10.0.19045.7184, 10.0.22631.6936, 10.0.26100.8246, 10.0.26200.8246, 10.0.20348.5020, 10.0.25398.2274

Confirm exposure before applying a vendor-supported change.

1
Identify
Confirm that Microsoft Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.