Local Code Execution Risk in Windows Fast FAT File System Driver

Historical catalog analysis: CISA added this entry on March 11, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2025-24985 is an integer overflow or wraparound vulnerability (CWE-190, CWE-122) located within the Microsoft Windows Fast FAT File System Driver. This flaw allows an unauthorized attacker with local access to the system to execute arbitrary code.

Exposure and applicability

This vulnerability affects systems running Microsoft Windows. In a healthcare environment, this is particularly relevant for:

• Clinical Workstations: Devices used by staff to access ePHI where local access might be gained via unauthorized physical or logical entry.
• Medical Device Controllers: Many medical devices rely on embedded Windows versions for control interfaces; if these systems utilize the Fast FAT File System Driver, they may be susceptible.
• Removable Media Interfaces: Because this involves a file system driver often associated with FAT-formatted media (such as USB drives), the risk is heightened in environments where removable storage is permitted.

Remediation priorities

Our analysis suggests that healthcare security leaders should prioritize remediation based on the level of local access available to untrusted users. While CISA has set a deadline of April 1, 2025, for federal agencies, private providers should use this as a benchmark for urgency.

1. Patch Deployment: Apply the official mitigations and updates provided by Microsoft. This is the primary method to address the underlying integer overflow.
2. Restrict Local Access: For high-risk systems—such as those controlling patient care equipment—limit physical access to USB ports and restrict local login privileges to authorized personnel only.
3. Removable Media Policy: Review and enforce policies regarding the use of FAT-formatted external drives on workstations that handle sensitive ePHI.

How to validate remediation

To verify that exposure has been reduced, organizations should employ the following methods:

• Update Verification: Security administrators can verify that the specific Microsoft security update addressing CVE-2025-24985 has been successfully installed across the fleet via centralized patch management logs.
• Configuration Audit: Clinical engineering teams should coordinate to ensure that medical device controllers are updated according to vendor-approved guidance, as unsupported changes to these devices can impact patient safety.

Limits and open questions

It is currently unknown if this vulnerability has been utilized in known ransomware campaigns. Furthermore, the source specifies that this is a local code execution vulnerability; it does not indicate that the flaw can be exploited remotely over a network without prior access to the system. The effectiveness of patching depends on the ability to update legacy systems that may no longer be supported by the vendor.

Source and editorial note

CVE-2025-24985: Microsoft Windows Fast FAT File System Driver Integer Overflow Vulnerability · Source date: March 11, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: March 14, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 18, 2026 at 01:26 UTC.

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