Executive brief
A security vulnerability exists in the Microsoft Windows Composite Image File System Driver, a component that manages how the operating system handles certain types of disk images and file systems. An attacker who already has basic access to a computer could exploit this flaw to view sensitive information that should normally be protected. This could lead to the exposure of private data or system secrets, though it does not allow the attacker to take full control of the machine or delete files directly.
Technical details
A type confusion vulnerability (CWE-843) exists in the Microsoft Composite Image File System (CimFS) Driver. The flaw occurs when the driver accesses a resource using an incompatible type, which can be triggered by a locally authenticated attacker. Successful exploitation allows the attacker to read sensitive information from the kernel or other protected memory spaces. The attack requires local access with low privileges and no user interaction. Microsoft has released security updates to address this issue across affected Windows 10, 11, and Server versions.
Affected products
- Microsoft Windows 10 Version 21H2 10.0.19044.0 to 10.0.19044.7548
- Microsoft Windows 10 Version 22H2 10.0.19045.0 to 10.0.19045.7548
- Microsoft Windows 11 Version 24H2 10.0.26100.0 to 10.0.26100.8875
- Microsoft Windows 11 Version 25H2 10.0.26200.0 to 10.0.26200.8875
- Microsoft Windows 11 version 26H1 10.0.28000.0 to 10.0.28000.2269
- Microsoft Windows Server 2022 10.0.20348.0 to 10.0.20348.5386
- Microsoft Windows Server 2025 10.0.26100.0 to 10.0.26100.33158
Timeline
- 2026-07-14: advisory: Initial publication by Microsoft and NVD
- 2026-07-14: patched: Security updates made available by Microsoft