CVE-2025-54091 is a vulnerability classified under CWE-190 (Integer Overflow or Wraparound) affecting Microsoft Windows 10 Version 1809, specifically the Hyper-V virtualization component. The flaw arises from improper handling of integer values within Hyper-V, leading to an overflow or wraparound condition. This can be exploited by an attacker with local access and limited privileges to escalate their privileges to higher levels, potentially SYSTEM or administrative privileges. The vulnerability does not require user interaction, making it more straightforward to exploit once local access is obtained. The CVSS v3.1 base score is 7.8, indicating high severity, with metrics showing low attack complexity, low privileges required, no user interaction, and high impact on confidentiality, integrity, and availability. Although no public exploits are known at this time, the vulnerability poses a significant risk to systems running this specific Windows 10 build, especially in environments using Hyper-V for virtualization. The lack of available patches at the time of publication increases the urgency for mitigation through alternative means. The vulnerability's exploitation could allow attackers to bypass security boundaries within virtualized environments, compromising sensitive data and system stability.

For European organizations, the impact of CVE-2025-54091 can be substantial, particularly for enterprises relying on Windows 10 Version 1809 with Hyper-V virtualization. Successful exploitation enables attackers to elevate privileges locally, potentially gaining administrative control over critical systems. This can lead to unauthorized access to confidential data, disruption of services, and the ability to deploy further attacks such as malware or ransomware. Organizations in sectors with high virtualization usage, including finance, manufacturing, and government, may face increased risk. The vulnerability's presence in an older Windows version means that organizations that have not upgraded or patched their systems remain exposed. Given the high impact on confidentiality, integrity, and availability, exploitation could result in significant operational and reputational damage, regulatory penalties under GDPR, and financial losses.

1. Upgrade affected systems to a supported and patched version of Windows 10 or later, as Microsoft typically addresses such vulnerabilities in cumulative updates. 2. If upgrading is not immediately feasible, restrict local access to systems running Windows 10 Version 1809, especially those with Hyper-V enabled, by enforcing strict access controls and network segmentation. 3. Monitor system logs and Hyper-V event logs for unusual privilege escalation attempts or anomalous behavior indicative of exploitation. 4. Employ endpoint detection and response (EDR) solutions capable of detecting privilege escalation techniques. 5. Disable Hyper-V on systems where virtualization is not required to reduce the attack surface. 6. Implement strict user account management policies to limit the number of users with local access and privileges. 7. Prepare incident response plans specifically addressing local privilege escalation scenarios. 8. Stay informed about Microsoft security advisories and apply patches promptly once available.