CVE-2025-32709 is a high-severity use-after-free vulnerability identified in the Windows Ancillary Function Driver for WinSock on Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability, classified under CWE-416, arises when the system improperly handles memory, leading to a scenario where a program continues to use memory after it has been freed. Specifically, the flaw exists in the network driver component responsible for ancillary functions related to WinSock, the Windows Sockets API that facilitates network communication. An authorized local attacker with limited privileges (PR:L) can exploit this vulnerability to execute arbitrary code in kernel mode, thereby elevating their privileges to SYSTEM level without requiring user interaction (UI:N). The vulnerability has a CVSS 3.1 base score of 7.8, reflecting its high impact on confidentiality, integrity, and availability (all rated high). The attack vector is local (AV:L), meaning the attacker must have access to the affected system, but the attack complexity is low (AC:L), indicating exploitation does not require specialized conditions. The vulnerability is currently published and recognized by Microsoft and CISA but has no known exploits in the wild yet. No patches or mitigations have been linked at the time of this report, emphasizing the need for vigilance and proactive defense. The flaw could allow attackers to bypass security boundaries, execute arbitrary code with elevated privileges, and potentially compromise the entire system, making it a critical concern for organizations still running Windows 10 Version 1809.

For European organizations, this vulnerability poses a significant risk, especially those relying on legacy systems or specialized applications that mandate Windows 10 Version 1809. Successful exploitation could lead to full system compromise, allowing attackers to access sensitive data, disrupt operations, or deploy ransomware and other malware with elevated privileges. Given the local attack vector, insider threats or attackers who gain initial access through other means could leverage this vulnerability to escalate privileges and move laterally within networks. This is particularly concerning for sectors with strict data protection requirements such as finance, healthcare, and critical infrastructure, where confidentiality and integrity are paramount. Additionally, the lack of user interaction requirement facilitates stealthy exploitation, increasing the risk of undetected breaches. The vulnerability could also undermine compliance with GDPR and other European cybersecurity regulations if exploited to exfiltrate personal or sensitive data. Organizations with limited patch management capabilities or those delaying upgrades are at heightened risk.

European organizations should prioritize upgrading or migrating systems from Windows 10 Version 1809 to a supported and patched version of Windows as soon as possible, as no patches are currently linked for this vulnerability. In the interim, implement strict access controls to limit local user privileges and restrict administrative rights to reduce the attack surface. Employ endpoint detection and response (EDR) solutions capable of monitoring suspicious kernel-level activities and anomalous network driver behavior. Conduct thorough audits of user accounts and remove or disable unnecessary local accounts to minimize potential attackers with local access. Network segmentation can help contain potential lateral movement if exploitation occurs. Additionally, organizations should enforce application whitelisting and leverage Windows Defender Exploit Guard features to mitigate exploitation attempts. Regularly monitor security advisories from Microsoft and CISA for updates or patches addressing this vulnerability. Finally, enhance user awareness and insider threat detection programs to identify and respond to potential local privilege escalation attempts promptly.