CVE-2026-72971: Microsoft Windows 11 26h1

Medium severity, CVSS 5.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Improper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to perform tampering locally.

Affected products

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

Published 2026-08-11. Last modified 2026-08-14.