CVE-2026-50667 is a Windows Common Log File System (CLFS) Driver elevation of privilege vulnerability caused by a race condition / improper synchronization. Microsoft rates it High severity with a CVSS v3.1 base score of 7.8 and temporal score of 6.8. The attack vector is LOCAL, attack complexity is LOW, privileges required are LOW, and user interaction is NONE. If exploited, an attacker could gain SYSTEM privileges. Microsoft reports no public disclosure and no known exploitation, but exploit likelihood is marked “Exploitation More Likely.” Because this is a local privilege escalation rather than a network attack, enterprise risk is highest on systems where untrusted local users or code can run.

Highlights:
- CVSS scores: Base 7.8 - Temporal 6.8
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN.
- Impact: Elevation of Privilege; confidentiality, integrity, and availability impacts are all HIGH. Successful exploitation can grant SYSTEM privileges.
- Exploitation likelihood: Exploitation More Likely, with a LOCAL vector, LOW attack complexity, LOW privileges required, and NO user interaction.
- Severity for enterprise: High technical severity, but lower exposure than remote vulnerabilities because exploitation requires local access. Risk is more relevant on shared or multi-user Windows systems, or where low-privilege code can execute locally.
- Patch status: available

Affected systems:
- Windows 10 1607
- Windows 10 1809
- Windows 10 21H2
- Windows 10 22H2
- Windows 11 24H2
- Windows 11 25H2
- Windows 11 26H1
- Windows 11 unspecified
- Windows Server 2012
- Windows Server 2012 R2
- Windows Server 2016
- Windows Server 2019
- Windows Server 2022
- Windows Server 2025