CVE-2026-40397

EUVD-2026-29659
Integer underflow (wrap or wraparound) in Windows Common Log File System Driver allows an authorized attacker to elevate privileges locally.
Wrap or Wraparound
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.8 HIGH
LOCAL
LOW
LOW
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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)
KB5087537
1809 (x64, x86)
KB5087538
21H2 (arm64, x64, x86)
KB5087544
22H2 (arm64, x64, x86)
KB5087544
Windows 11
23H2 (arm64, x64)
KB5087420
24H2 (arm64, x64)
KB5089549
25H2 (arm64, x64)
KB5089549
26H1 (arm64, x64)
KB5089548
Windows Server 2012
Server Core
KB5087470
Standard
KB5087470
Windows Server 2012 R2
Server Core
KB5087471
Standard
KB5087471
Windows Server 2016
Server Core
KB5087537
Standard
KB5087537
Windows Server 2019
Server Core
KB5087538
Standard
KB5087538
Windows Server 2022
23H2 Server Core
KB5087541
Server Core
KB5087545
Standard
KB5087545
Windows Server 2025
Server Core
KB5087539
Standard
KB5087539
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40397