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 vulnerability arises due to improper synchronization when concurrently accessing shared resources, classified under CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization). This flaw allows an authorized local attacker—someone with limited privileges on the affected system—to exploit the race condition to elevate their privileges. By manipulating the timing of operations on shared resources, the attacker can gain higher-level access rights, potentially leading to full system compromise. The vulnerability impacts confidentiality, integrity, and availability, as it can allow unauthorized access to sensitive data, modification of system configurations, and disruption of services. The CVSS v3.1 score is 7.0, reflecting a high severity level, with attack vector local (AV:L), requiring high attack complexity (AC:H), low privileges (PR:L), no user interaction (UI:N), and unchanged scope (S:U). No known exploits are currently reported in the wild, and no patches have yet been published. The vulnerability was reserved in mid-July 2025 and published in early September 2025, indicating recent discovery and disclosure. The Server Core installation is a minimalistic Windows Server configuration commonly used in enterprise environments for enhanced security and reduced attack surface, but this vulnerability undermines that security by allowing privilege escalation through a race condition in a core system component.

For European organizations, this vulnerability poses a significant risk, particularly for enterprises and service providers relying on Windows Server 2025 Server Core installations for critical infrastructure, cloud services, and data centers. Privilege escalation vulnerabilities can lead to unauthorized administrative access, enabling attackers to deploy malware, exfiltrate sensitive data, disrupt operations, or pivot to other network segments. Given the high confidentiality, integrity, and availability impact, organizations handling regulated data—such as financial institutions, healthcare providers, and government agencies—face increased compliance and operational risks. The local attack vector means that initial access is required, but in environments where multiple users or services have limited access, the vulnerability could be exploited by insiders or attackers who have gained foothold through other means. The lack of a patch at this time necessitates immediate risk mitigation to prevent potential exploitation. Additionally, the Server Core installation is often used in automated and containerized environments, which could amplify the impact if exploited in cloud or hybrid infrastructures prevalent in Europe.

1. Immediate mitigation should focus on minimizing local access to Windows Server 2025 Server Core systems by enforcing strict access controls and monitoring for unusual privilege escalation attempts. 2. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious behavior indicative of race condition exploitation. 3. Isolate critical servers using network segmentation and limit administrative access to trusted personnel only. 4. Implement robust logging and auditing to detect early signs of exploitation attempts. 5. Until an official patch is released, consider deploying temporary workarounds such as disabling or restricting the Microsoft Brokering File System component if feasible without disrupting operations. 6. Regularly review and update privilege assignments to ensure the principle of least privilege is enforced. 7. Prepare for rapid deployment of patches once available by maintaining an up-to-date asset inventory and patch management process. 8. Conduct internal penetration testing and vulnerability assessments focusing on privilege escalation vectors to identify and remediate related weaknesses.