CVE-2026-83855: Microsoft Windows 11 Version 23h2

High severity, CVSS 7.5. EPSS: 1.2% chance of exploitation in the next 30 days.

Integer underflow (wrap or wraparound) in Windows WLAN Service allows an unauthorized attacker to deny service over a network.

Affected products

• Microsoft Windows 11 Version 23h2: from 10.0.22631.0, before 10.0.22631.7652 (fixed in 10.0.22631.7652)
• Microsoft Windows 11 Version 24h2: from 10.0.26100.0, before 10.0.26100.9711 (fixed in 10.0.26100.9711)
• Microsoft Windows 11 Version 25h2: from 10.0.26200.0, before 10.0.26200.9711 (fixed in 10.0.26200.9711)
• Microsoft Windows 11 Version 26h1: from 10.0.28000.0, before 10.0.28000.3231 (fixed in 10.0.28000.3231)
• Microsoft Windows 11 Version 26h2: from 10.0.26300.0, before 10.0.26300.9711 (fixed in 10.0.26300.9711)
• Microsoft Windows Server 2025: from 10.0.26100.0, before 10.0.26100.33650 (fixed in 10.0.26100.33650)
• Microsoft Windows Server 2025 Server Core Installation: from 10.0.26100.0, before 10.0.26100.33650 (fixed in 10.0.26100.33650)

Published 2026-10-13. Last modified 2026-10-13.