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 2012 | 6.2.9200.0 – < 6.2.9200.26079 | 6.2.9200.26079 |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 – < 6.2.9200.26079 | 6.2.9200.26079 |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 – < 6.3.9600.23181 | 6.3.9600.23181 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 – < 6.3.9600.23181 | 6.3.9600.23181 |
| 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 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
nhh9905/CVE-2026-34344 ★ 3 · Aug 13, 2026
CVE 1-day in afd.sys
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
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-2026-34344 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