CVE-2025-59188 is a vulnerability identified in Microsoft Windows Server 2019, specifically within the Windows Failover Cluster component. The issue is classified under CWE-200, indicating an exposure of sensitive information to unauthorized actors. The vulnerability allows an attacker who already has some level of local authorization (low privileges) to disclose sensitive information from the cluster environment. This exposure does not require user interaction and does not impact the integrity or availability of the system, focusing solely on confidentiality. The CVSS v3.1 base score is 5.5 (medium), with an attack vector limited to local access (AV:L), low attack complexity (AC:L), and requiring privileges (PR:L). The scope remains unchanged (S:U), and the impact is high on confidentiality (C:H) but none on integrity (I:N) or availability (A:N). The vulnerability was reserved in early September 2025 and published in mid-October 2025. No patches or known exploits are currently available, indicating that the vulnerability is newly disclosed and not yet actively exploited. The Windows Failover Cluster is a critical feature used to provide high availability and redundancy for enterprise applications and services, making this vulnerability relevant for organizations relying on clustered Windows Server environments.

For European organizations, the exposure of sensitive information in Windows Server 2019 Failover Clusters could lead to unauthorized disclosure of confidential data, potentially including configuration details, cluster state information, or other sensitive operational data. This could facilitate further attacks or unauthorized access if leveraged by malicious insiders or attackers with local access. Sectors such as finance, healthcare, telecommunications, and critical infrastructure that rely heavily on Windows Server clustering for high availability are particularly at risk. The impact is primarily on confidentiality, which could result in data breaches, compliance violations (e.g., GDPR), and reputational damage. Since exploitation requires local access and some privileges, the threat is mitigated somewhat by existing access controls but remains significant in environments with multiple administrators or where endpoint security is weak. The absence of known exploits reduces immediate risk but underscores the need for proactive mitigation.

1. Restrict local access to Windows Server 2019 Failover Cluster nodes strictly to trusted administrators and personnel. 2. Implement robust privilege management and enforce the principle of least privilege to minimize the number of users with cluster access. 3. Monitor cluster logs and system events for unusual access patterns or attempts to access sensitive cluster information. 4. Use endpoint detection and response (EDR) solutions to detect potential misuse of local privileges. 5. Until a patch is released, consider isolating cluster nodes in secure network segments to reduce the risk of unauthorized local access. 6. Regularly review and audit cluster configurations and access permissions. 7. Stay informed on Microsoft security advisories and apply patches promptly once available. 8. Employ multi-factor authentication for administrative access where possible to reduce risk of credential compromise.