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-2025-24991 is an out-of-bounds read vulnerability (CWE-125) located within the Microsoft Windows New Technology File System (NTFS). This flaw allows an attacker who already possesses authorized access to a system to disclose information locally. Unlike vulnerabilities that allow remote execution, this specific issue focuses on local information disclosure.
Exposure and applicability
This vulnerability is applicable to healthcare organizations utilizing Microsoft Windows environments for their infrastructure. Because NTFS is the primary file system for Windows, the exposure extends to any system where ePHI is stored or processed locally, including workstations in clinical settings, local file servers, and administrative terminals.
For HIPAA-covered entities and business associates, this represents a risk to the confidentiality of data at rest. While the attacker must already be authorized on the system, the ability to disclose information locally could potentially be used to bypass certain internal data protections or gather intelligence for further privilege escalation within a healthcare network.
Remediation priorities
Our analysis suggests that remediation should be prioritized based on the sensitivity of the data stored on the affected Windows systems. We recommend the following actions:
- Apply Vendor Mitigations: The primary priority is to apply the updates provided by Microsoft. This addresses the root cause of the out-of-bounds read.
- Review Local Access Controls: Since this vulnerability requires an authorized attacker, security leaders should review who has local access to systems housing ePHI to reduce the pool of potential internal threats.
- Audit High-Value Assets: Prioritize patching for servers and workstations that handle highly sensitive patient records or serve as gateways to larger clinical databases.
How to validate remediation
To verify that the risk has been reduced, organizations should employ the following validation methods:
- Patch Verification: Use authorized system management tools to confirm that the specific Microsoft security update addressing CVE-2025-24991 has been successfully installed across all targeted endpoints.
- Configuration Audit: Review system logs and access lists to ensure that local authorization is restricted to necessary personnel, limiting the potential for an authorized user to exploit the flaw.
Note: A version check confirms a patch was applied but does not guarantee total security against all possible attack vectors.
Limits and open questions
It remains unknown whether this vulnerability has been utilized in ransomware campaigns. Additionally, while CISA has set a remediation deadline of April 1, 2025, for federal agencies, this date is a federal guideline and not a legal mandate for private healthcare providers, though it serves as a useful benchmark for risk management.
There are inherent limitations to these mitigations; patching the file system addresses this specific out-of-bounds read but does not eliminate other potential vulnerabilities within the OS. Residual risk remains regarding existing authorized users who may already have established persistence or elevated privileges on the system.
Source and editorial note
CVE-2025-24991: Microsoft Windows NTFS Out-Of-Bounds Read 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 01:31 UTC.
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