CVE-2025-47973 is a high-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) involving a buffer over-read condition in the Virtual Hard Disk (VHDX) component. The vulnerability is classified under CWE-126, which pertains to buffer over-read issues where a program reads data beyond the boundaries of a buffer. In this case, the flaw allows an unauthorized local attacker to elevate privileges on the affected system. The attack vector requires local access (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but does require user interaction (UI:R). The scope is unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). This means that exploitation can lead to full system compromise, including unauthorized disclosure, modification, or destruction of data. The vulnerability arises from improper handling of VHDX files, which are used to represent virtual hard disks in Windows environments. An attacker could craft a malicious VHDX file that triggers the buffer over-read when processed by the system, potentially leading to memory corruption and privilege escalation. Although no known exploits are currently reported in the wild, the high CVSS score of 7.8 and the critical impact on system security make this a significant threat, especially for environments still running the affected Windows 10 version 1809, which is an older release but may still be in use in some organizations.

For European organizations, this vulnerability poses a serious risk, particularly in sectors relying on legacy Windows 10 1809 systems, such as industrial control, healthcare, government, and critical infrastructure. Successful exploitation could allow attackers to gain elevated privileges locally, bypassing security controls and potentially deploying further malware or ransomware. This could lead to data breaches, operational disruptions, and loss of sensitive information. Given the high impact on confidentiality, integrity, and availability, organizations could face regulatory penalties under GDPR if personal data is compromised. Additionally, the requirement for user interaction means phishing or social engineering could be used to trick users into opening malicious VHDX files, increasing the attack surface. The lack of known exploits in the wild currently provides a window for proactive mitigation before widespread exploitation occurs.

1. Immediate patching is the most effective mitigation; however, no patch links are currently provided, so organizations should monitor Microsoft security advisories closely for updates addressing CVE-2025-47973. 2. Restrict the use and opening of VHDX files from untrusted or unknown sources, especially via email or removable media. 3. Employ application whitelisting and endpoint protection solutions that can detect or block suspicious VHDX file handling or abnormal privilege escalation attempts. 4. Implement strict user privilege policies to minimize the number of users with local administrative rights, reducing the impact of potential exploitation. 5. Conduct user awareness training focused on the risks of opening unexpected files and recognizing social engineering attempts. 6. For organizations unable to upgrade from Windows 10 Version 1809 promptly, consider isolating affected systems from critical networks and applying compensating controls such as enhanced monitoring and intrusion detection to identify exploitation attempts early.