Executive brief
A security vulnerability has been identified in the Windows Common Log File System (CLFS) driver, a core component used by the operating system for data logging. An attacker who already has basic access to a computer could exploit this flaw to gain full administrative control over the system. This could allow them to bypass security restrictions, access sensitive data, or install malicious software.
Technical details
A use-after-free (CWE-416) vulnerability exists within the Windows Common Log File System (CLFS) driver (clfs.sys). The flaw is triggered when the driver improperly manages memory objects during log file operations, allowing an attacker to reference memory after it has been freed. To exploit this, an attacker must have local access to the target system with low-privileged user credentials. Successful exploitation enables the attacker to execute arbitrary code with SYSTEM privileges, effectively gaining full control over the affected host. Microsoft has released security updates to address this issue.
Affected products
- Microsoft Windows
Timeline
- 2026-06-09: disclosed: Vulnerability published by Microsoft and NVD.
- 2026-06-09: patched: Security updates made available by Microsoft.