CVE-2026-85880: Microsoft Windows Heap-Based Buffer Overflow Vulnerability

High severity, CVSS 7.8. Actively exploited: in CISA KEV since 2026-09-08. EPSS: 3.6% chance of exploitation in the next 30 days.

Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.

Affected products

• Microsoft Windows 10 1607: before 10.0.14393.9512 (fixed in 10.0.14393.9512)
• Microsoft Windows 10 1809: before 10.0.17763.9245 (fixed in 10.0.17763.9245)
• Microsoft Windows 10 21h2: before 10.0.19044.7725 (fixed in 10.0.19044.7725)
• Microsoft Windows 10 22h2: before 10.0.19045.7725 (fixed in 10.0.19045.7725)
• Microsoft Windows Server 2012: affected versions not specified; version r2 only
• Microsoft Windows Server 2016: before 10.0.14393.9512 (fixed in 10.0.14393.9512)
• Microsoft Windows Server 2019: before 10.0.17763.9245 (fixed in 10.0.17763.9245)
• Microsoft Windows Server 2022: before 10.0.20348.5622 (fixed in 10.0.20348.5622)

Published 2026-09-08. Last modified 2026-09-24.