CVE-2026-34335: Microsoft Windows 10 1607

High severity, CVSS 7.0. EPSS: 0.3% chance of exploitation in the next 30 days.

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

Affected products

• Microsoft Windows 10 1607: before 10.0.14393.9234 (fixed in 10.0.14393.9234)
• Microsoft Windows 10 1809: before 10.0.17763.8880 (fixed in 10.0.17763.8880)
• Microsoft Windows 10 21h2: before 10.0.19044.7417 (fixed in 10.0.19044.7417)
• Microsoft Windows 10 22h2: before 10.0.19045.7417 (fixed in 10.0.19045.7417)
• Microsoft Windows 11 23h2: before 10.0.22631.7219 (fixed in 10.0.22631.7219)
• Microsoft Windows 11 24h2: before 10.0.26100.8655 (fixed in 10.0.26100.8655)
• Microsoft Windows 11 25h2: before 10.0.26200.8655 (fixed in 10.0.26200.8655)
• Microsoft Windows 11 26h1: before 10.0.28000.2269 (fixed in 10.0.28000.2269)
• Microsoft Windows Server 2012: affected versions not specified; version r2 only
• Microsoft Windows Server 2016: before 10.0.14393.9234 (fixed in 10.0.14393.9234)
• Microsoft Windows Server 2019: before 10.0.17763.8880 (fixed in 10.0.17763.8880)
• Microsoft Windows Server 2022: before 10.0.20348.5256 (fixed in 10.0.20348.5256)
• Microsoft Windows Server 2025: before 10.0.26100.32995 (fixed in 10.0.26100.32995)

Published 2026-06-09. Last modified 2026-07-23.