CVE-2025-53141 is a vulnerability identified in the Windows Ancillary Function Driver for WinSock component of Microsoft Windows 10 Version 1809 (build 17763.0). The flaw is a null pointer dereference (CWE-476), which occurs when the driver attempts to access memory through a pointer that has not been properly initialized or has been set to null. This leads to a system crash or unexpected behavior that can be exploited by an authorized local attacker to elevate their privileges on the affected system. The attacker must have local access and some level of authorization but does not require user interaction to trigger the vulnerability. Exploiting this flaw can allow the attacker to gain higher privileges, potentially leading to full system compromise, including unauthorized access to sensitive data, modification of system configurations, or disruption of system availability. The CVSS v3.1 base score of 7.8 reflects the high impact on confidentiality, integrity, and availability, combined with relatively low attack complexity and the need for only limited privileges. No public exploits or patches are currently available, increasing the urgency for organizations to prepare mitigations and monitor for exploitation attempts. This vulnerability is particularly relevant for legacy systems still running Windows 10 Version 1809, which remains in use in various enterprise environments.

For European organizations, the impact of CVE-2025-53141 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 unauthorized access to sensitive corporate data, disruption of critical services, and compromise of system integrity. This can affect confidentiality by exposing sensitive information, integrity by allowing unauthorized changes to system files or configurations, and availability by causing system crashes or denial of service. Organizations in finance, healthcare, government, and critical infrastructure sectors are particularly at risk due to the sensitivity and regulatory requirements of their data. The lack of a patch and known exploits in the wild means attackers may develop exploits rapidly, increasing the threat window. Additionally, the vulnerability could be leveraged as a stepping stone for lateral movement within networks, amplifying its impact on enterprise environments.

1. Restrict local access to systems running Windows 10 Version 1809 by enforcing strict physical and logical access controls, including the use of strong authentication and role-based access. 2. Monitor system logs and security events for unusual local privilege escalation attempts or crashes related to the WinSock driver. 3. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious activities indicative of exploitation attempts. 4. Prepare for rapid deployment of official patches or updates from Microsoft once released; consider testing patches in isolated environments before full deployment. 5. Where feasible, plan and accelerate migration from Windows 10 Version 1809 to supported, updated Windows versions to reduce exposure to this and other legacy vulnerabilities. 6. Educate IT and security teams about this vulnerability to ensure timely detection and response. 7. Use network segmentation to limit the ability of an attacker who gains local access to move laterally within the network.