CVE-2026-50428: Microsoft Windows 11 26h1

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

Out-of-bounds read in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to disclose information locally.

Affected products

• Microsoft Windows 11 26h1: before 10.0.28000.2269 (fixed in 10.0.28000.2269); before 10.0.28000.2525 (fixed in 10.0.28000.2525)

Published 2026-07-14. Last modified 2026-07-22.