CVE-2026-40378

HighCVSS 7.5/10Last modified Jul 22, 2026

Description

Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.

Metrics

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

Weakness enumeration

CWE-789

Affected software

Vendor	Product	Versions
Microsoft	Windows 10 Version 1607	>= 10.0.14393.0, < 10.0.14393.9339
Microsoft	Windows 10 Version 1809	>= 10.0.17763.0, < 10.0.17763.9020
Microsoft	Windows 10 Version 21H2	>= 10.0.19044.0, < 10.0.19044.7548
Microsoft	Windows 10 Version 22H2	>= 10.0.19045.0, < 10.0.19045.7548
Microsoft	Windows 11 version 23H2	>= 10.0.22631.0, < 10.0.22631.7376
Microsoft	Windows 11 Version 23H2	>= 10.0.22631.0, < 10.0.22631.7376
Microsoft	Windows 11 Version 24H2	>= 10.0.26100.0, < 10.0.26100.8875
Microsoft	Windows 11 Version 25H2	>= 10.0.26200.0, < 10.0.26200.8875
Microsoft	Windows 11 version 26H1	>= 10.0.28000.0, < 10.0.28000.2525
Microsoft	Windows Server 2012	>= 6.2.9200.0, < 6.2.9200.26226
Microsoft	Windows Server 2012 (Server Core installation)	>= 6.2.9200.0, < 6.2.9200.26226
Microsoft	Windows Server 2012 R2	>= 6.3.9600.0, < 6.3.9600.23291
Microsoft	Windows Server 2012 R2 (Server Core installation)	>= 6.3.9600.0, < 6.3.9600.23291
Microsoft	Windows Server 2016	>= 10.0.14393.0, < 10.0.14393.9339
Microsoft	Windows Server 2016 (Server Core installation)	>= 10.0.14393.0, < 10.0.14393.9339
Microsoft	Windows Server 2019	>= 10.0.17763.0, < 10.0.17763.9020
Microsoft	Windows Server 2019 (Server Core installation)	>= 10.0.17763.0, < 10.0.17763.9020
Microsoft	Windows Server 2022	>= 10.0.20348.0, < 10.0.20348.5386
Microsoft	Windows Server 2025	>= 10.0.26100.0, < 10.0.26100.33158
Microsoft	Windows Server 2025 (Server Core installation)	>= 10.0.26100.0, < 10.0.26100.33158

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40378Vendor Advisory

Timeline

Published: Jul 14, 2026
Last modified: Jul 22, 2026
NVD status: Analyzed

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