CVE-2026-70578: Microsoft Windows 10 21h2

High severity, CVSS 7.0. EPSS: 0.3% chance of exploitation in the next 30 days.

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

Affected products

• 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 11 23h2: before 10.0.22631.7582 (fixed in 10.0.22631.7582)
• Microsoft Windows 11 24h2: before 10.0.26100.9445 (fixed in 10.0.26100.9445)
• Microsoft Windows 11 25h2: before 10.0.26200.9445 (fixed in 10.0.26200.9445)
• Microsoft Windows 11 26h1: before 10.0.28000.2954 (fixed in 10.0.28000.2954)

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