CVE-2026-21245: Windows Kernel Elevation of Privilege Vulnerability
This Microsoft advisory covers CVE-2026-21245 in Windows Server 2025 (Server Core installation).
- CVE-2026-21245
Key facts
- Vendor rating
- High, CVSS 7.8
- CISA KEV
- Not listed (catalogue checked )
- Affected
- Windows 11 Version 24H2 10.0.26100.0 before 10.0.26100.7840; Windows 11 Version 25H2 10.0.26200.0 before 10.0.26200.7840; Windows 11 version 26H1 10.0.28000.0 before 10.0.28000.1575 and 3 more below
- Fixed in
- 10.0.26100.7840, 10.0.26200.7840, 10.0.28000.1575 and 1 more below
- Source published
- Source revised
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
Description
Heap-based buffer overflow in Windows Kernel allows an authorized attacker to elevate privileges locally.
Affected products named by the advisory: Windows Server 2025; Windows Server 2025 (Server Core installation).
Text from the source record.
- Windows 11 Version 24H2 10.0.26100.0 before 10.0.26100.7840
- Windows 11 Version 25H2 10.0.26200.0 before 10.0.26200.7840
- Windows 11 version 26H1 10.0.28000.0 before 10.0.28000.1575
- Windows 11 Version 26H1 10.0.28000.0 before 10.0.28000.1575
- Windows Server 2025 10.0.26100.0 before 10.0.26100.32370
- Windows Server 2025 (Server Core installation) 10.0.26100.0 before 10.0.26100.32370
Official advisory · high-confidence parse· fetched ·verify at source
How to fix CVE-2026-21245
Upgrade to a fixed release named by Microsoft:
- 10.0.26100.7840
- 10.0.26200.7840
- 10.0.28000.1575
- 10.0.26100.32370
End-of-life dates for Windows Server
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Microsoft Server advisories, February 2026All Microsoft Server advisories
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