CVE-2025-49762 is a race condition vulnerability classified under CWE-362, found in the Windows Ancillary Function Driver for WinSock component of Microsoft Windows 10 Version 1809 (build 17763.0). The vulnerability arises from improper synchronization when multiple threads or processes concurrently access shared resources, leading to a race condition. This flaw can be exploited by an attacker who already has local access with limited privileges to elevate their privileges on the affected system. The race condition allows the attacker to manipulate the timing of operations to gain unauthorized access or control, potentially compromising system confidentiality, integrity, and availability. The vulnerability does not require user interaction but does require the attacker to have local access and the ability to execute code with limited privileges. The CVSS 3.1 score of 7.0 reflects a high severity, with attack vector local, attack complexity high, privileges required low, and no user interaction needed. No public exploits or patches are currently available, increasing the urgency for monitoring and mitigation. The vulnerability is particularly concerning for environments where Windows 10 Version 1809 remains in use, as this version is out of mainstream support and may lack other security improvements. The flaw could be leveraged in targeted attacks to gain administrative control, enabling further lateral movement or persistence within a network.

For European organizations, the impact of CVE-2025-49762 can be significant, especially in sectors relying on legacy Windows 10 Version 1809 systems. Successful exploitation allows local attackers to escalate privileges, potentially leading to full system compromise. This can result in unauthorized access to sensitive data, disruption of critical services, and the deployment of further malware or ransomware. Organizations in finance, healthcare, government, and critical infrastructure sectors are at heightened risk due to the sensitivity of their data and the critical nature of their operations. The vulnerability could facilitate insider threats or attacks originating from compromised local accounts. Since Windows 10 Version 1809 is no longer widely supported, many organizations may not have applied necessary updates, increasing exposure. Additionally, the high attack complexity and requirement for local access limit remote exploitation but do not eliminate risk from insider threats or attackers who have gained initial footholds. The lack of known exploits in the wild provides a window for proactive defense but also means attackers may develop exploits targeting this vulnerability soon.

1. Prioritize upgrading affected systems from Windows 10 Version 1809 to a supported and fully patched Windows version to eliminate exposure to this vulnerability. 2. Until upgrades are complete, implement strict local access controls and limit user privileges to the minimum necessary to reduce the risk of privilege escalation. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor for suspicious local activity indicative of exploitation attempts. 4. Use system hardening techniques such as disabling unnecessary services and restricting access to the WinSock ancillary driver where possible. 5. Monitor system and security logs for anomalies related to process synchronization or privilege escalation attempts. 6. Educate IT staff and users about the risks of local privilege escalation and the importance of reporting unusual system behavior. 7. Prepare incident response plans specifically addressing potential exploitation of race condition vulnerabilities. 8. Engage with Microsoft support channels for any out-of-band patches or mitigations that may become available. 9. Conduct regular vulnerability assessments focusing on legacy systems to identify and remediate similar risks proactively.