Executive brief
A security vulnerability has been identified in the Windows Cloud Files Mini Filter Driver, a component that manages how files are synced between your computer and cloud storage services like 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
A vulnerability classified as an untrusted pointer dereference (CWE-822) exists within the Windows Cloud Files Mini Filter Driver (cldflt.sys). The flaw occurs when the driver fails to properly validate a pointer provided by a user-mode application before dereferencing it in kernel mode. An attacker with low-privileged local access can exploit this by passing a specially crafted pointer to the driver, leading to arbitrary code execution with SYSTEM privileges. 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 Version 1809 10.0.17763.0 to 10.0.17763.8276
- Microsoft Windows 10 Version 21H2 10.0.19044.0 to 10.0.19044.6809
- Microsoft Windows 10 Version 22H2 10.0.19045.0 to 10.0.19045.6809
- Microsoft Windows 11 Version 22H3 10.0.22631.0 to 10.0.22631.6491
- Microsoft Windows 11 Version 23H2 10.0.22631.0 to 10.0.22631.6491
- Microsoft Windows 11 Version 24H2 10.0.26100.0 to 10.0.26100.7623
- Microsoft Windows 11 Version 25H2 10.0.26200.0 to 10.0.26200.7623
- Microsoft Windows Server 2019 10.0.17763.0 to 10.0.17763.8276
- Microsoft Windows Server 2022 Before 2026-01-13 patch
Timeline
- 2026-01-13: disclosed: Initial publication of the vulnerability details.
- 2026-01-13: patched: Microsoft released security updates as part of Patch Tuesday.