CVE-2026-62772: Microsoft Windows 11 26h1

High severity, CVSS 7.8. EPSS: 0.3% chance of exploitation in the next 30 days.

Heap-based buffer overflow in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

Affected products

• Microsoft Windows 11 26h1: before 10.0.28000.2704 (fixed in 10.0.28000.2704)

Published 2026-08-11. Last modified 2026-08-13.