Elevation of Privilege Vulnerability in Windows Common Log File System Driver
CVE-2026-40397

7.8HIGH

Key Information:

Vendor

Microsoft
Status
Windows 10 Version 1607
Windows 10 Version 1809
Windows 10 Version 21h2
Windows 10 Version 22h2
Vendor
CVE Published:
12 May 2026

What is CVE-2026-40397?

An integer underflow vulnerability in the Windows Common Log File System Driver can be exploited by an authorized attacker to elevate privileges on affected systems. By manipulating the way the driver handles certain data, an attacker may gain higher access rights, allowing them to execute unauthorized actions or gain control over system resources.

Affected Version(s)

Windows 10 Version 1607 32-bit Systems 10.0.14393.0 < 10.0.14393.9140

Windows 10 Version 1809 32-bit Systems 10.0.17763.0 < 10.0.17763.8755

Windows 10 Version 21H2 32-bit Systems 10.0.19044.0 < 10.0.19044.7291

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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