CVE-2025-59186 is a vulnerability classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) affecting Microsoft Windows Server 2019, specifically version 10.0.17763.0. The vulnerability resides in the Windows Kernel and allows an attacker with local authorized access to disclose sensitive information that should otherwise be protected. The flaw arises from improper handling of kernel data, which can be read by an attacker with low privileges, potentially revealing critical system or user information. The CVSS v3.1 base score is 5.5 (medium severity), reflecting that the attack vector is local (AV:L), requires low privileges (PR:L), and no user interaction (UI:N) is needed. The impact is limited to confidentiality (C:H), with no effect on integrity or availability. No known exploits are currently reported in the wild, and no patches have been released at the time of publication (October 14, 2025). The vulnerability's existence emphasizes the risk posed by local access threats and the importance of kernel-level protections. Since the vulnerability does not require elevated privileges beyond low-level local access, it could be exploited by malicious insiders or through compromised accounts. The lack of patches necessitates interim mitigations until official fixes are available.

For European organizations, the primary impact of CVE-2025-59186 is the potential unauthorized disclosure of sensitive information stored or processed within Windows Server 2019 environments. This could include system configuration details, user data, or other confidential information residing in kernel memory. Such exposure may facilitate further attacks, including privilege escalation or targeted intrusions, if attackers leverage disclosed data. Sectors handling sensitive or regulated data—such as finance, healthcare, government, and critical infrastructure—are particularly at risk. The requirement for local access limits remote exploitation but increases the threat from insider attacks or attackers who have already gained limited footholds. The absence of integrity or availability impact reduces the risk of service disruption but does not diminish the confidentiality concerns. European organizations with extensive Windows Server 2019 deployments, especially those in countries with high adoption rates of Microsoft server products, face a tangible risk of data leakage. The vulnerability could also affect compliance with data protection regulations like GDPR if sensitive personal data is exposed.

1. Restrict local access to Windows Server 2019 systems to trusted personnel only, enforcing strict access control policies and least privilege principles. 2. Monitor and audit local user activities on affected servers to detect unusual or unauthorized access attempts, using endpoint detection and response (EDR) tools. 3. Implement network segmentation to limit lateral movement and reduce the number of users with local access to critical servers. 4. Disable or limit unnecessary local accounts and services that could be leveraged to exploit this vulnerability. 5. Prepare for timely deployment of official patches from Microsoft once released; establish a patch management process prioritizing this vulnerability. 6. Consider deploying kernel-level security solutions or enhanced monitoring that can detect anomalous kernel memory access patterns. 7. Educate system administrators and security teams about the vulnerability to increase awareness and readiness. 8. Use application whitelisting and endpoint protection to reduce the risk of local privilege abuse that could lead to exploitation.