CVE-2025-58714 is a vulnerability classified under CWE-284 (Improper Access Control) found in the Ancillary Function Driver for WinSock component of Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). This flaw allows an attacker who already has some level of authorized local access to escalate their privileges to a higher level, potentially SYSTEM or administrative privileges. The vulnerability arises because the access control mechanisms governing the WinSock ancillary driver are insufficiently restrictive, enabling privilege escalation without requiring user interaction. The CVSS v3.1 score of 7.8 reflects high impact on confidentiality, integrity, and availability, with low attack complexity and requiring only low privileges to exploit. Although no exploits are currently known in the wild, the vulnerability's nature makes it a significant risk in environments where multiple users share systems or where attackers can gain initial footholds with limited privileges. The flaw could be leveraged to bypass security controls, install persistent malware, or access sensitive data. The vulnerability was reserved in early September 2025 and published in mid-October 2025, with no patch links currently available, indicating that remediation may be pending or in progress.

For European organizations, this vulnerability poses a substantial risk, particularly in sectors with high reliance on Windows 11 25H2 such as finance, healthcare, government, and critical infrastructure. Successful exploitation could lead to unauthorized access to sensitive information, disruption of services, and compromise of system integrity. The ability to elevate privileges locally means that attackers who gain limited access—through phishing, insider threats, or other means—can expand their control over affected systems. This could facilitate lateral movement within networks and deployment of ransomware or espionage tools. Given the widespread adoption of Windows 11 in Europe, the vulnerability could affect a broad range of enterprises and public sector entities. The lack of known exploits currently provides a window for proactive mitigation, but the high severity score underscores the urgency of addressing the issue before active exploitation emerges.

1. Monitor Microsoft security advisories closely and apply official patches immediately upon release to address this vulnerability. 2. Implement strict local user privilege management, ensuring users have only the minimum necessary permissions to reduce the risk of privilege escalation. 3. Employ application whitelisting and endpoint detection and response (EDR) tools to detect anomalous privilege escalation attempts related to WinSock or ancillary drivers. 4. Restrict local administrative access and regularly audit user accounts and group memberships to prevent unauthorized privilege assignments. 5. Use network segmentation to limit the impact of compromised systems and contain potential lateral movement. 6. Educate users and administrators about the risks of privilege escalation and the importance of maintaining updated systems. 7. Consider deploying enhanced logging and monitoring focused on WinSock driver activity and privilege changes to enable early detection of exploitation attempts.