High · 7.0 CVE-2026-34345 EUVD-2026-29604GHSA-j2x4-j6jv-hpjv

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Published May 12, 2026 · Updated Aug 10, 2026 · Assigned by microsoft

Vendor: Microsoft Product: Windows 10 Version 1607 Product: Windows 10 Version 1809 Product: Windows 10 Version 21H2 Product: Windows 10 Version 22H2 Product: Windows 11 version 23H2 Product: Windows 11 Version 24H2 Product: Windows 11 Version 25H2 Product: Windows 11 version 26H1 Product: Windows Server 2016 Product: Windows Server 2016 (Server Core installation) Product: Windows Server 2019 Product: Windows Server 2019 (Server Core installation) Product: Windows Server 2022 Product: Windows Server 2022, 23H2 Edition (Server Core installation) Product: Windows Server 2025 Product: Windows Server 2025 (Server Core installation) Platform: Windows

Description

Access of resource using incompatible type ('type confusion') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Affected products

Vendor	Product	Affected	Fixed
Microsoft	Windows 10 Version 1607	10.0.14393.0 – < 10.0.14393.9140	10.0.14393.9140
Microsoft	Windows 10 Version 1809	10.0.17763.0 – < 10.0.17763.8755	10.0.17763.8755
Microsoft	Windows 10 Version 21H2	10.0.19044.0 – < 10.0.19044.7291	10.0.19044.7291
Microsoft	Windows 10 Version 22H2	10.0.19045.0 – < 10.0.19045.7417	10.0.19045.7417
Microsoft	Windows 11 version 23H2	10.0.22631.0 – < 10.0.22631.7079, 10.0.22631.0 – < 10.0.22631.7219	10.0.22631.7079
Microsoft	Windows 11 Version 24H2	10.0.26100.0 – < 10.0.26100.8457	10.0.26100.8457
Microsoft	Windows 11 Version 25H2	10.0.26200.0 – < 10.0.26200.8457	10.0.26200.8457
Microsoft	Windows 11 version 26H1	10.0.28000.0 – < 10.0.28000.2113	10.0.28000.2113
Microsoft	Windows Server 2016	10.0.14393.0 – < 10.0.14393.9140	10.0.14393.9140
Microsoft	Windows Server 2016 (Server Core installation)	10.0.14393.0 – < 10.0.14393.9140	10.0.14393.9140
Microsoft	Windows Server 2019	10.0.17763.0 – < 10.0.17763.8755	10.0.17763.8755
Microsoft	Windows Server 2019 (Server Core installation)	10.0.17763.0 – < 10.0.17763.8755	10.0.17763.8755
Microsoft	Windows Server 2022	10.0.20348.0 – < 10.0.20348.5139	10.0.20348.5139
Microsoft	Windows Server 2022, 23H2 Edition (Server Core installation)	10.0.25398.0 – < 10.0.25398.2330	10.0.25398.2330
Microsoft	Windows Server 2025	10.0.26100.0 – < 10.0.26100.32860	10.0.26100.32860
Microsoft	Windows Server 2025 (Server Core installation)	10.0.26100.0 – < 10.0.26100.32860	10.0.26100.32860

Advisories 3

WID-SEC-2026-1489 Microsoft Windows Produkte: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 8, 2026
NCSC-2026-0141 Kwetsbaarheden verholpen in Microsoft Windows NCSC-NL (Netherlands) · Jun 2, 2026
MSRC-CVE-2026-34345 Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability Microsoft Security Response Center · May 12, 2026

References

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability vendor-advisory patch