CVE-2026-69544: 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 SMB Client allows an authorized attacker to elevate privileges locally.

Affected products

• Microsoft Windows 11 26h1: before 10.0.28000.2954 (fixed in 10.0.28000.2954)

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