CVE-2025-49762 is a high-severity race condition vulnerability identified in the Windows Ancillary Function Driver for WinSock component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability arises from improper synchronization during concurrent execution when accessing shared resources, classified under CWE-362. An authorized local attacker can exploit this race condition to elevate privileges on the affected system. The flaw allows the attacker to manipulate the timing of resource access, potentially bypassing security controls and gaining higher privileges than intended. The vulnerability requires local access with low privileges and does not require user interaction, but it has a high attack complexity due to the need for precise timing to trigger the race condition. The CVSS v3.1 base score is 7.0, reflecting high impact on confidentiality, integrity, and availability, as successful exploitation can lead to full system compromise. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability affects a specific legacy Windows 10 version (1809), which is still in use in some environments, particularly in enterprise and industrial settings where long-term support versions are preferred. The race condition in a core networking driver component (WinSock) is critical because it can undermine the security model of the operating system, allowing privilege escalation from a low-privileged user to SYSTEM or equivalent. This can facilitate further attacks such as installing persistent malware, disabling security controls, or accessing sensitive data.

For European organizations, this vulnerability poses a significant risk, especially for those still running Windows 10 Version 1809 in production environments. Privilege escalation vulnerabilities can lead to full system compromise, data breaches, and disruption of critical services. Organizations in sectors such as finance, healthcare, manufacturing, and government are particularly at risk due to the sensitive nature of their data and the criticality of their IT infrastructure. Exploitation could enable attackers to bypass endpoint security, move laterally within networks, and establish persistence. Given the local access requirement, the threat is more pronounced in environments where insider threats or compromised user accounts exist. The lack of user interaction requirement increases the risk of automated exploitation once local access is obtained. The absence of known exploits in the wild provides a window for mitigation, but also means organizations should proactively assess and remediate this vulnerability to prevent future attacks. The impact on confidentiality, integrity, and availability is high, potentially leading to data theft, system manipulation, and service outages.

European organizations should prioritize upgrading or patching affected systems as soon as Microsoft releases an official fix. In the interim, organizations should: 1) Identify and inventory all systems running Windows 10 Version 1809 to understand exposure. 2) Restrict local access rights and enforce the principle of least privilege to minimize the number of users who can exploit this vulnerability. 3) Implement strict access controls and monitoring on endpoints, especially those with network-facing roles or elevated privileges. 4) Use endpoint detection and response (EDR) solutions to detect suspicious behavior indicative of privilege escalation attempts. 5) Apply application whitelisting and restrict execution of unauthorized code to reduce the attack surface. 6) Conduct user awareness training to reduce insider threat risks. 7) Consider upgrading to a more recent Windows 10 version or Windows 11, which are not affected by this vulnerability. 8) Monitor security advisories from Microsoft and threat intelligence feeds for updates on exploit availability and patches. These targeted steps go beyond generic advice by focusing on access control, monitoring, and system inventory specific to the affected legacy OS version.