CVE-2026-40399

HighCVSS 7.8/10Last modified Nov 11, 2026

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP allows an authorized attacker to elevate privileges locally.

Metrics

CVSS 3.1 7.8/10CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-121

Affected software

Vendor	Product	Versions
Microsoft	Windows 10 Version 1607	>= 10.0.14393.0, < 10.0.14393.9140
Microsoft	Windows 10 Version 1809	>= 10.0.17763.0, < 10.0.17763.8755
Microsoft	Windows 10 Version 21H2	>= 10.0.19044.0, < 10.0.19044.7291
Microsoft	Windows 10 Version 22H2	>= 10.0.19045.0, < 10.0.19045.7417
Microsoft	Windows 11 version 23H2	>= 10.0.22631.0, < 10.0.22631.7079
Microsoft	Windows 11 Version 23H2	>= 10.0.22631.0, < 10.0.22631.7219
Microsoft	Windows 11 Version 24H2	>= 10.0.26100.0, < 10.0.26100.8457
Microsoft	Windows 11 Version 25H2	>= 10.0.26200.0, < 10.0.26200.8457
Microsoft	Windows 11 version 26H1	>= 10.0.28000.0, < 10.0.28000.2113
Microsoft	Windows Server 2016	>= 10.0.14393.0, < 10.0.14393.9140
Microsoft	Windows Server 2016 (Server Core installation)	>= 10.0.14393.0, < 10.0.14393.9140
Microsoft	Windows Server 2019	>= 10.0.17763.0, < 10.0.17763.8755
Microsoft	Windows Server 2019 (Server Core installation)	>= 10.0.17763.0, < 10.0.17763.8755
Microsoft	Windows Server 2022	>= 10.0.20348.0, < 10.0.20348.5139
Microsoft	Windows Server 2022, 23H2 Edition (Server Core installation)	>= 10.0.25398.0, < 10.0.25398.2330
Microsoft	Windows Server 2025	>= 10.0.26100.0, < 10.0.26100.32860
Microsoft	Windows Server 2025 (Server Core installation)	>= 10.0.26100.0, < 10.0.26100.32860

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40399Vendor Advisory

Timeline

Published: May 12, 2026
Last modified: Nov 11, 2026
NVD status: Modified

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