CVE-2025-54105 is a high-severity race condition vulnerability identified in the Microsoft Brokering File System component of Windows Server 2025, specifically affecting the Server Core installation (version 10.0.26100.0). The flaw arises from improper synchronization during concurrent execution of shared resources, classified under CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization). This race condition allows an authorized local attacker with low privileges to exploit the timing window to elevate their privileges on the affected system. The vulnerability impacts confidentiality, integrity, and availability, as successful exploitation can grant attackers elevated rights, potentially enabling them to execute arbitrary code, access sensitive data, or disrupt system operations. The CVSS v3.1 base score is 7.0, reflecting a high severity with attack vector limited to local access, requiring high attack complexity and low privileges but no user interaction. No known exploits are currently reported in the wild, and no official patches have been linked yet. The Server Core installation, often used in enterprise environments for its minimal footprint and reduced attack surface, is nonetheless vulnerable due to this synchronization flaw in a critical file system component. The vulnerability does not require user interaction but does require local access and some privileges, making it a significant concern for internal threat actors or compromised accounts.

For European organizations, this vulnerability poses a substantial risk, especially for enterprises and service providers relying on Windows Server 2025 Server Core installations for critical infrastructure, data centers, and cloud services. Elevation of privilege vulnerabilities can lead to lateral movement within networks, unauthorized data access, and disruption of services. Given the high confidentiality, integrity, and availability impact, exploitation could compromise sensitive business data, intellectual property, and customer information, potentially violating GDPR and other data protection regulations. The local attack vector means insider threats or attackers with initial footholds could escalate privileges, making internal security controls and monitoring crucial. The lack of a patch at this time increases exposure, and organizations may face operational challenges in mitigating risk until updates are available. This vulnerability also raises concerns for managed service providers and cloud operators in Europe who deploy Windows Server 2025 Server Core instances, as compromise could cascade to multiple clients.

1. Restrict local access strictly to trusted administrators and users with a clear need, minimizing the number of accounts with any level of privilege on affected servers. 2. Implement robust endpoint detection and response (EDR) solutions to monitor for suspicious local privilege escalation attempts and anomalous process behaviors. 3. Employ application whitelisting and strict execution policies to limit unauthorized code execution even if privilege escalation occurs. 4. Use virtualization-based security features and hardware-enforced isolation where possible to contain potential exploits. 5. Regularly audit and harden server configurations, removing unnecessary services and accounts to reduce attack surface. 6. Monitor Microsoft’s security advisories closely for the release of patches or workarounds and plan immediate deployment once available. 7. Consider network segmentation to isolate critical Windows Server 2025 Server Core installations from less trusted network zones to limit lateral movement. 8. Conduct internal penetration testing and red team exercises focusing on local privilege escalation scenarios to validate defenses.