CVE-2026-20921

HighCVSS 7.5/10Last modified Jul 30, 2026

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.

Metrics

CVSS 3.1 7.5/10CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-362

Affected software

VendorProductVersions
MicrosoftWindows 10 Version 1607>= 10.0.14393.0, < 10.0.14393.8783
MicrosoftWindows 10 Version 1809>= 10.0.17763.0, < 10.0.17763.8276
MicrosoftWindows 10 Version 21H2>= 10.0.19044.0, < 10.0.19044.6809
MicrosoftWindows 10 Version 22H2>= 10.0.19045.0, < 10.0.19045.6809
MicrosoftWindows 11 version 23H2>= 10.0.22631.0, < 10.0.22631.6491
MicrosoftWindows 11 Version 23H2>= 10.0.22631.0, < 10.0.22631.6491
MicrosoftWindows 11 Version 24H2>= 10.0.26100.0, < 10.0.26100.7623
MicrosoftWindows 11 Version 25H2>= 10.0.26200.0, < 10.0.26200.7623
MicrosoftWindows Server 2008 R2 Service Pack 1>= 6.1.7601.0, < 6.1.7601.28117
MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)>= 6.1.7601.0, < 6.1.7601.28117
MicrosoftWindows Server 2008 Service Pack 2>= 6.0.6003.0, < 6.0.6003.23717
MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)>= 6.0.6003.0, < 6.0.6003.23717
MicrosoftWindows Server 2012>= 6.2.9200.0, < 6.2.9200.25868
MicrosoftWindows Server 2012 (Server Core installation)>= 6.2.9200.0, < 6.2.9200.25868
MicrosoftWindows Server 2012 R2>= 6.3.9600.0, < 6.3.9600.22968
MicrosoftWindows Server 2012 R2 (Server Core installation)>= 6.3.9600.0, < 6.3.9600.22968
MicrosoftWindows Server 2016>= 10.0.14393.0, < 10.0.14393.8783
MicrosoftWindows Server 2016 (Server Core installation)>= 10.0.14393.0, < 10.0.14393.8783
MicrosoftWindows Server 2019>= 10.0.17763.0, < 10.0.17763.8276
MicrosoftWindows Server 2019 (Server Core installation)>= 10.0.17763.0, < 10.0.17763.8276
MicrosoftWindows Server 2022>= 10.0.20348.0, < 10.0.20348.4648
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)>= 10.0.25398.0, < 10.0.25398.2092
MicrosoftWindows Server 2025>= 10.0.26100.0, < 10.0.26100.32230
MicrosoftWindows Server 2025 (Server Core installation)>= 10.0.26100.0, < 10.0.26100.32230

References

Timeline

Published
Jan 13, 2026
Last modified
Jul 30, 2026
NVD status
Modified

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CVE-2026-20921: High severity, CVSS 7.5 | Vulnix