CVE-2025-47973 is a high-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability is classified as a buffer over-read (CWE-126) occurring within the Virtual Hard Disk (VHDX) component of the operating system. A buffer over-read happens when a program reads data beyond the boundaries of a buffer, potentially exposing sensitive information or causing system instability. In this case, the flaw allows an unauthorized local attacker to elevate privileges by exploiting the improper handling of VHDX files. The CVSS v3.1 base score is 7.8, indicating a high impact on confidentiality, integrity, and availability. The attack vector is local (AV:L), requiring low attack complexity (AC:L), no privileges (PR:N), but does require user interaction (UI:R). The scope is unchanged (S:U), and the impact is high across confidentiality, integrity, and availability (C:H/I:H/A:H). Although no known exploits are currently reported in the wild, the vulnerability’s nature suggests that successful exploitation could allow an attacker to gain elevated privileges on affected systems, potentially leading to full system compromise or lateral movement within a network. The vulnerability affects only Windows 10 Version 1809, which is an older release, but still may be in use in some environments. No official patches or mitigation links have been published yet, indicating that organizations should prioritize monitoring and prepare for patch deployment once available.

For European organizations, the impact of CVE-2025-47973 could be significant, especially in sectors where legacy Windows 10 Version 1809 systems remain operational, such as manufacturing, healthcare, and government agencies that often have longer upgrade cycles. The ability for a local attacker to elevate privileges means that any user with limited access could potentially gain administrative control, leading to unauthorized data access, disruption of services, or deployment of malware including ransomware. This could compromise sensitive personal data protected under GDPR, resulting in regulatory penalties and reputational damage. Additionally, the high impact on system integrity and availability could disrupt critical business operations. Since the vulnerability requires local access and user interaction, the threat is more pronounced in environments with less strict endpoint security controls or where social engineering tactics could be used to trick users into opening malicious VHDX files. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits following public disclosure.

European organizations should take proactive and specific steps beyond generic advice: 1) Conduct an inventory to identify all systems running Windows 10 Version 1809 and assess their criticality. 2) Implement strict endpoint protection measures that monitor and restrict the execution of untrusted VHDX files, including application whitelisting and behavior-based detection. 3) Enforce the principle of least privilege to limit user permissions and reduce the potential impact of privilege escalation. 4) Educate users about the risks of opening unknown or unsolicited VHDX files, emphasizing social engineering awareness. 5) Isolate legacy systems from critical network segments to contain potential breaches. 6) Monitor system logs and security alerts for unusual activities related to VHDX file handling or privilege escalations. 7) Prepare for rapid deployment of patches once Microsoft releases an official fix, including testing in controlled environments. 8) Consider upgrading affected systems to supported Windows versions where this vulnerability is not present or has been patched.