Executive brief
A security vulnerability exists in the Windows component responsible for managing cloud-based files, such as those used by OneDrive. 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 view sensitive data, install malicious software, or disrupt business operations.
Technical details
This vulnerability is classified as a use-after-free (CWE-416) within the Windows Cloud Files Mini Filter Driver (cldflt.sys). The flaw is triggered when the driver incorrectly manages memory objects during file operations, allowing an attacker to execute code in kernel mode. To exploit this, an attacker must first have local access to the target system with low-level user privileges. Successful exploitation results in a complete local privilege escalation (LPE), granting the attacker SYSTEM-level access. Microsoft has released security updates to address this issue across affected versions of Windows 10, Windows 11, and Windows Server.
Affected products
- Microsoft Windows 10 1809, 21H2, 22H2
- Microsoft Windows 11 24H2, 25H2, 26H1
- Microsoft Windows Server 2019 All versions
- Microsoft Windows Server 2022 All versions
Timeline
- 2026-07-14: disclosed
- 2026-07-14: advisory