CVE-2025-47971 is a buffer over-read vulnerability classified under CWE-126, affecting the Virtual Hard Disk (VHDX) handling component in Microsoft Windows 10 Version 1507 (build 10.0.10240.0). The vulnerability arises from improper bounds checking when processing VHDX files, which can cause the system to read beyond allocated memory buffers. This flaw can be exploited by an unauthorized local attacker who convinces a user to interact with a maliciously crafted VHDX file, triggering the over-read condition. The consequence is a local privilege escalation, allowing the attacker to gain elevated system privileges from a non-privileged context. The CVSS v3.1 base score is 7.8, reflecting high severity due to the impact on confidentiality, integrity, and availability, combined with low attack complexity and no required privileges prior to exploitation. The vulnerability does not require prior authentication but does require user interaction, such as mounting or opening a malicious VHDX file. No patches or exploit code are currently publicly available, but the vulnerability is officially published and reserved since May 2025. The affected Windows 10 version is an early release (1507), which is largely superseded by newer versions but may still be in use in legacy environments. The vulnerability's exploitation could allow attackers to bypass security controls, execute arbitrary code with elevated privileges, and compromise system integrity and confidentiality.

The impact of CVE-2025-47971 is significant for organizations still running Windows 10 Version 1507, particularly in environments where legacy systems remain operational. Successful exploitation enables local attackers to escalate privileges, potentially leading to full system compromise. This can result in unauthorized access to sensitive data, disruption of system operations, and the ability to install persistent malware or backdoors. The vulnerability affects confidentiality by exposing memory contents beyond intended boundaries, integrity by allowing unauthorized modification of system state, and availability by potentially causing system instability or crashes. Although exploitation requires local access and user interaction, insider threats or attackers who gain initial footholds via other means could leverage this vulnerability to deepen their control. The lack of known exploits in the wild currently reduces immediate risk, but the high severity score and the nature of the vulnerability make it a critical concern for legacy system security. Organizations relying on this Windows 10 version face increased risk of targeted attacks, especially in sectors with high-value data or critical infrastructure.

1. Upgrade affected systems from Windows 10 Version 1507 to the latest supported Windows 10 or Windows 11 versions, as this early build is no longer supported and lacks security updates. 2. Until upgrades are feasible, restrict local user access to trusted personnel only and enforce strict access controls to prevent unauthorized local logins. 3. Disable or restrict usage of VHDX files and virtual disk mounting where possible, especially from untrusted sources. 4. Implement application whitelisting and endpoint protection solutions that can detect and block attempts to open or mount suspicious VHDX files. 5. Monitor system logs and security event logs for unusual activity related to virtual disk operations or privilege escalations. 6. Educate users about the risks of opening untrusted VHDX files and enforce policies against executing unknown or suspicious files. 7. Once Microsoft releases official patches or updates addressing this vulnerability, apply them promptly and verify successful deployment. 8. Employ network segmentation and least privilege principles to limit the impact of potential local compromises. These measures go beyond generic advice by focusing on legacy system management, access control, and proactive monitoring specific to the VHDX attack vector.