CVE-2026-40378

EUVD-2026-43790
Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Windows Releases
Platform
Version
Windows 10
1607 (x64, x86)
KB5099535
1809 (x64, x86)
KB5099538
21H2 (arm64, x64, x86)
KB5099539
22H2 (arm64, x64, x86)
KB5099539
Windows 11
23H2 (arm64, x64)
KB5099414
24H2 (arm64, x64)
KB5101650
25H2 (arm64, x64)
KB5101650
26H1 (arm64, x64)
KB5095051
Windows Server 2012
Server Core
KB5099445
Standard
KB5099445
Windows Server 2012 R2
Server Core
KB5099444
Standard
KB5099444
Windows Server 2016
Server Core
KB5099535
Standard
KB5099535
Windows Server 2019
Server Core
KB5099538
Standard
KB5099538
Windows Server 2022
Standard
KB5099540
Windows Server 2025
Server Core
KB5099536
Standard
KB5099536
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40378