CVE-2026-20840

Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.

Score

CVSS 3.1 7.8 High

Status

Analyzed - secure@microsoft.com

Published

2026-01-13

Last modified

2026-07-30

Weaknesses

CWE-122

Affected products

• Windows 10 1607 (Microsoft)
• Windows 10 1809 (Microsoft)
• Windows 10 21H2 (Microsoft)
• Windows 10 21h2 (Microsoft)
• Windows 10 22H2 (Microsoft)
• Windows 10 22h2 (Microsoft)
• Windows 11 23H2 (Microsoft)
• Windows 11 23h2 (Microsoft)
• Windows 11 24H2 (Microsoft)
• Windows 11 24h2 (Microsoft)
• Windows 11 25H2 (Microsoft)
• Windows 11 25h2 (Microsoft)
• Windows Server 2008 (Microsoft)
• Windows Server 2008 R2 (Microsoft)
• Windows Server 2008 Sp2 (Microsoft)
• Windows Server 2012 (Microsoft)
• Windows Server 2012 R2 (Microsoft)
• Windows Server 2016 (Microsoft)
• Windows Server 2019 (Microsoft)
• Windows Server 2022 (Microsoft)
• Windows Server 2022 23h2 (Microsoft)
• Windows Server 2025 (Microsoft)
• Windows Server 23h2 (Microsoft)

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20840