CVE-2025-55680 is a vulnerability classified under CWE-367, a time-of-check to time-of-use (TOCTOU) race condition, found in the Windows Cloud Files Mini Filter Driver component of Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). This race condition occurs when the system checks a resource's state and then uses it, but the state changes between these two operations, allowing an attacker to exploit the timing gap. In this case, an authorized local attacker can manipulate the timing to gain elevated privileges on the system. The vulnerability does not require user interaction but does require local privileges, meaning the attacker must already have some level of access to the system. The impact is severe, affecting confidentiality, integrity, and availability, as the attacker can potentially execute code with higher privileges, modify system files, or disrupt system operations. The CVSS v3.1 score is 7.8, reflecting high severity with low attack complexity and no user interaction needed. No public exploits have been reported yet, and no patches have been linked at the time of publication, indicating that mitigation is pending. The vulnerability is particularly concerning because the Cloud Files Mini Filter Driver is involved in managing cloud file synchronization, a common feature in modern Windows environments, increasing the attack surface.

For European organizations, this vulnerability poses a significant risk due to the widespread adoption of Windows 11 25H2 in enterprise and government environments. Successful exploitation could allow attackers to escalate privileges locally, potentially leading to full system compromise, unauthorized access to sensitive data, disruption of critical services, and persistence within networks. Organizations handling sensitive personal data under GDPR could face compliance risks if breaches occur. Critical infrastructure sectors such as finance, healthcare, and public administration, which rely heavily on Windows environments, are particularly vulnerable. The lack of user interaction requirement lowers the barrier for exploitation once local access is obtained, increasing the threat from insider threats or attackers who have gained initial footholds. Although no known exploits are currently active, the high severity and potential impact necessitate proactive measures to prevent exploitation and limit damage.

1. Monitor Microsoft security advisories closely and apply official patches immediately once released to address CVE-2025-55680. 2. Restrict local user privileges rigorously, ensuring that only trusted personnel have access to systems running Windows 11 25H2. 3. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous behavior related to privilege escalation attempts. 4. Harden systems by disabling or restricting the Cloud Files Mini Filter Driver if it is not required for business operations, reducing the attack surface. 5. Conduct regular audits of local accounts and permissions to minimize the number of users with elevated privileges. 6. Employ strict network segmentation to limit lateral movement in case of compromise. 7. Educate IT staff about the nature of TOCTOU vulnerabilities and the importance of timely patching and monitoring. 8. Use behavioral analytics to detect unusual file system or driver activity that could indicate exploitation attempts. 9. Maintain comprehensive logging and ensure logs are protected and regularly reviewed for signs of suspicious activity related to this vulnerability.