CVE-2025-59275 is a vulnerability identified in Microsoft Windows 10 Version 1809 (build 17763.0) that involves improper validation of the specified type of input within Windows Authentication Methods. This flaw is categorized under CWE-1287, which relates to improper validation of input types, and is further associated with memory safety issues (CWE-125 and CWE-122) indicating potential buffer overflows or out-of-bounds reads/writes. The vulnerability allows an attacker with authorized local access—meaning the attacker must already have some level of access to the system—to escalate their privileges without requiring user interaction. The CVSS v3.1 score of 7.8 reflects a high severity, with attack vector local (AV:L), low attack complexity (AC:L), and requiring low privileges (PR:L). The vulnerability impacts confidentiality, integrity, and availability at a high level, suggesting that successful exploitation could lead to full system compromise, including unauthorized access to sensitive data, modification of system files, or denial of service. No public exploits or active exploitation in the wild have been reported as of the publication date. The lack of available patches at the time of reporting indicates that organizations must prepare for imminent updates from Microsoft. This vulnerability is particularly relevant for environments where Windows 10 Version 1809 remains in use, including legacy systems and certain industrial control systems. The improper input validation in authentication mechanisms could be exploited by attackers to bypass security controls and gain elevated privileges, potentially leading to lateral movement or persistence within a network.

For European organizations, the impact of CVE-2025-59275 can be significant, especially in sectors relying on Windows 10 Version 1809, such as manufacturing, healthcare, government, and critical infrastructure. Successful exploitation allows attackers to elevate privileges locally, which can lead to unauthorized access to sensitive information, disruption of services, and potential deployment of further malware or ransomware. The high impact on confidentiality, integrity, and availability means that data breaches, system tampering, and operational downtime are realistic consequences. Organizations with legacy systems or delayed patching cycles are particularly vulnerable. Additionally, the vulnerability could be leveraged as a stepping stone for more complex attacks within corporate or governmental networks. Given the local attack vector, insider threats or attackers who have gained initial footholds through other means could exploit this flaw to escalate privileges and compromise entire systems or networks.

1. Apply Microsoft security updates promptly once patches for CVE-2025-59275 are released; monitor official Microsoft channels for patch availability. 2. Restrict local user privileges to the minimum necessary, employing the principle of least privilege to reduce the risk of privilege escalation. 3. Implement application whitelisting and endpoint protection solutions capable of detecting abnormal privilege escalation attempts. 4. Conduct regular audits of user accounts and permissions to identify and remove unnecessary local administrative rights. 5. Employ network segmentation to limit the spread of an attacker who gains local access. 6. Use enhanced logging and monitoring to detect suspicious authentication or privilege escalation activities. 7. For legacy systems that cannot be immediately updated, consider isolating them from critical networks or restricting physical and remote access. 8. Educate users and administrators about the risks of local privilege escalation and the importance of maintaining updated systems.