CVE-2025-54091 is a high-severity vulnerability identified in Microsoft Windows 10 Version 1809, specifically affecting the Hyper-V component. The root cause is an integer overflow or wraparound condition (CWE-190) within the Hyper-V virtualization platform. This flaw allows an authorized local attacker—someone with existing privileges on the system—to exploit the vulnerability to elevate their privileges further. The integer overflow likely occurs due to improper handling of arithmetic operations on integer variables, which can result in unexpected behavior such as buffer overflows or memory corruption. Such conditions can be leveraged by attackers to execute arbitrary code with elevated privileges or to bypass security restrictions. The CVSS v3.1 base score of 7.8 reflects the significant impact on confidentiality, integrity, and availability, with low attack complexity and requiring only local privileges without user interaction. The vulnerability does not currently have known exploits in the wild, but given the critical nature of Hyper-V in managing virtual machines, exploitation could lead to full system compromise or escape from virtualized environments. Since Windows 10 Version 1809 is an older release, it is possible that many systems remain unpatched or unsupported, increasing exposure risk. No official patches or mitigation links are provided yet, indicating that organizations must be vigilant and monitor for updates from Microsoft.

For European organizations, the impact of CVE-2025-54091 can be substantial, especially for enterprises relying on Windows 10 Version 1809 with Hyper-V for virtualization infrastructure. Successful exploitation could allow attackers to escalate privileges locally, potentially leading to full control over host systems and the ability to manipulate or disrupt virtual machines. This can compromise sensitive data confidentiality, integrity of critical systems, and availability of services hosted on virtualized environments. Industries such as finance, healthcare, government, and critical infrastructure operators that use Hyper-V for workload isolation and virtualization are at particular risk. The vulnerability could facilitate lateral movement within networks if attackers gain elevated privileges on endpoint or server systems. Additionally, since the flaw requires local access, insider threats or attackers who have already compromised lower-privilege accounts could leverage this vulnerability to deepen their foothold. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as exploit code could emerge rapidly once details become public.

1. Immediate mitigation involves upgrading affected systems from Windows 10 Version 1809 to a more recent, supported Windows version where this vulnerability is addressed. 2. If upgrading is not immediately feasible, organizations should restrict local access to systems running Hyper-V, enforcing strict access controls and monitoring for suspicious activity. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous privilege escalation attempts. 4. Regularly audit and minimize the number of users with local privileges to reduce the attack surface. 5. Monitor Microsoft security advisories closely for patches or workarounds related to CVE-2025-54091 and apply them promptly once available. 6. Consider disabling Hyper-V on systems where virtualization is not required to eliminate the attack vector. 7. Implement network segmentation to isolate critical systems and limit lateral movement opportunities in case of compromise. 8. Conduct user training to raise awareness about the risks of local privilege escalation and the importance of maintaining updated systems.