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 allows an attacker with authorized local access and low privileges to exploit the timing issue to elevate their privileges on the affected system. The attacker does not require user interaction to trigger the exploit, but must have some level of local access, such as a standard user account. The vulnerability impacts confidentiality, integrity, and availability by potentially granting elevated privileges, which could be leveraged to execute arbitrary code, access sensitive data, or disrupt system operations. The CVSS v3.1 base score is 7.0 (high), with attack vector local, attack complexity high, privileges required low, no user interaction, and scope unchanged. No public exploits or patches are currently available, increasing the urgency for organizations to monitor and prepare mitigation strategies. This vulnerability is particularly concerning for environments that still operate Windows 10 Version 1809, which is an older release and may not receive regular security updates. The flaw's presence in a core networking driver (WinSock) further elevates the risk, as it could be exploited to compromise networked systems and services.

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 attackers to escalate privileges locally, potentially leading to full system compromise. This can result in unauthorized access to sensitive data, disruption of critical services, and lateral movement within corporate networks. Organizations in finance, healthcare, government, and critical infrastructure sectors are particularly vulnerable due to the high value of their data and services. The vulnerability's exploitation could facilitate ransomware deployment, data breaches, or sabotage of essential services. Given that the attack requires local access, insider threats or attackers who have already gained limited footholds could leverage this flaw to deepen their control. The lack of known exploits in the wild provides a window for proactive defense, but also means detection may be difficult if exploitation begins. The outdated nature of the affected Windows version means many organizations may have already migrated, but those that have not remain at elevated risk.

1. Upgrade affected systems from Windows 10 Version 1809 to a supported and fully patched Windows version to eliminate the vulnerability. 2. If upgrading is not immediately feasible, implement strict access controls to limit local user privileges and restrict access to sensitive systems. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious local privilege escalation attempts. 4. Regularly audit and monitor logs for unusual activity indicative of race condition exploitation or privilege escalation. 5. Isolate legacy systems from critical network segments to reduce the risk of lateral movement. 6. Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of maintaining updated systems. 7. Prepare incident response plans specifically addressing local privilege escalation scenarios. 8. Engage with Microsoft support or security advisories for any forthcoming patches or mitigations related to this CVE. 9. Use virtualization or sandboxing techniques for legacy applications to contain potential exploitation. 10. Review and harden WinSock-related configurations and network driver permissions where possible.