Executive brief
A security vulnerability exists in the Windows Cloud Files Mini Filter Driver, a component that manages how files are synced between a computer and cloud storage. An attacker who already has basic access to a system could exploit this flaw to gain full administrative control. This could allow them to view sensitive data, install malicious software, or disrupt business operations.
Technical details
A heap-based buffer overflow vulnerability exists in the Windows Cloud Files Mini Filter Driver (cldflt.sys). The flaw is categorized as an untrusted pointer dereference (CWE-822) that leads to a buffer overflow condition. An attacker with local access and low-level privileges can exploit this vulnerability by sending specially crafted requests to the driver. Successful exploitation allows the attacker to execute code with SYSTEM privileges, effectively taking full control of the affected host. Microsoft has released security updates to address this issue across various versions of Windows and Windows Server.
Affected products
- Microsoft Windows 10 1607, 1809, 21H2, 22H2
- Microsoft Windows 11 22H3, 23H2
- Microsoft Windows Server 2008 SP2, R2 SP1
Timeline
- 2026-01-13: disclosed
- 2026-01-13: advisory