CVE-2025-54116 is a high-severity vulnerability classified under CWE-284 (Improper Access Control) affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw resides in the Windows MultiPoint Services component, which is designed to enable multiple users to simultaneously share one computer. The vulnerability allows an authorized attacker with local access and limited privileges to escalate their privileges on the affected system. Specifically, the attacker must have some level of access (local privileges) and perform user interaction to exploit this flaw, but the access control weakness permits them to elevate their privileges to a higher level, potentially SYSTEM or administrator. The CVSS v3.1 base score is 7.3, indicating a high severity due to the combination of local attack vector, low attack complexity, required privileges, and user interaction. The impact metrics indicate high confidentiality, integrity, and availability impacts, meaning successful exploitation could lead to full system compromise, unauthorized data access, and disruption of services. No known exploits are currently reported in the wild, and no patches have been linked yet, though the vulnerability was published on September 9, 2025. The vulnerability is limited to a specific Windows 10 version (1809), which is an older release but may still be in use in some environments, especially those with legacy systems or delayed upgrade cycles.

For European organizations, this vulnerability poses a significant risk especially in environments where Windows 10 Version 1809 is still operational. Organizations in sectors such as government, healthcare, education, and critical infrastructure that rely on legacy Windows systems could face elevated risks of privilege escalation attacks. Successful exploitation could allow attackers to bypass security controls, gain administrative access, and potentially deploy malware, exfiltrate sensitive data, or disrupt operations. Given the high impact on confidentiality, integrity, and availability, this vulnerability could facilitate lateral movement within networks and compromise sensitive information protected under regulations such as GDPR. The requirement for local access and user interaction somewhat limits remote exploitation but insider threats or social engineering attacks could leverage this vulnerability. The lack of known exploits in the wild currently provides a window for mitigation before active exploitation begins.

1. Immediate identification and inventory of all systems running Windows 10 Version 1809 within the organization. 2. Prioritize upgrading or patching affected systems as soon as Microsoft releases an official security update addressing CVE-2025-54116. 3. Until patches are available, restrict local access to affected systems by enforcing strict access controls and monitoring for unusual privilege escalation attempts. 4. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious activities related to privilege escalation. 5. Conduct user awareness training to reduce the risk of social engineering that could facilitate user interaction required for exploitation. 6. Employ network segmentation to limit the impact of a compromised system and prevent lateral movement. 7. Regularly audit and review user privileges to ensure least privilege principles are enforced. 8. Monitor system logs and security alerts for signs of exploitation attempts targeting MultiPoint Services or privilege escalation behaviors.