CVE-2025-47979 is a vulnerability classified under CWE-532, which concerns the insertion of sensitive information into log files. This specific issue affects Microsoft Windows Server 2025, particularly the Server Core installation variant, within the Windows Failover Cluster component. The vulnerability allows an authorized attacker with local privileges (low-level privileges) to access sensitive information that is improperly logged by the system. The CVSS 3.1 base score is 5.5 (medium), reflecting that the attack vector is local (AV:L), requires low complexity (AC:L), and low privileges (PR:L), with no user interaction (UI:N). The scope is unchanged (S:U), and the impact is high on confidentiality (C:H) but none on integrity (I:N) or availability (A:N). The vulnerability arises because sensitive data such as credentials, tokens, or configuration secrets may be written to log files without adequate protection or redaction, allowing local attackers to read these logs and gain unauthorized insight into sensitive operational details. No known exploits have been reported in the wild, and no patches have been released yet, though the vulnerability was reserved in May 2025 and published in October 2025. The lack of remote exploitation and the requirement for local access limit the attack surface, but in environments where multiple users have local access or where attackers can escalate privileges to local accounts, this vulnerability can lead to information disclosure that could facilitate further attacks or lateral movement within a network.

For European organizations, especially those operating critical infrastructure, financial services, or large enterprise environments using Windows Server 2025 with failover clustering, this vulnerability poses a risk of sensitive information leakage. The confidentiality breach could expose credentials, cluster configuration details, or other sensitive operational data that attackers could leverage for privilege escalation or lateral movement. Although the vulnerability requires local access, insider threats or attackers who have already compromised lower-privileged accounts could exploit this to gain further foothold. This risk is particularly relevant in shared hosting environments, data centers, or managed service providers where multiple users have local access. The impact on confidentiality could lead to data breaches, regulatory non-compliance (e.g., GDPR), and operational disruptions if attackers use disclosed information to disrupt cluster operations. However, since integrity and availability are not affected, the immediate operational impact is limited to information disclosure rather than service disruption.

To mitigate CVE-2025-47979, European organizations should implement strict access controls on systems running Windows Server 2025 Server Core installations with failover clustering. Limit local user accounts and enforce the principle of least privilege to reduce the number of users who can access sensitive logs. Regularly audit and monitor access to log files, ensuring that permissions prevent unauthorized reading. Employ centralized log management solutions that can securely collect and store logs off the local system to reduce exposure. Until a patch is released, consider disabling or restricting failover cluster logging features if feasible, or apply configuration changes to minimize sensitive data being logged. Additionally, implement strong endpoint security controls to detect and prevent unauthorized local access or privilege escalation attempts. Once Microsoft releases a patch or update, prioritize its deployment in all affected environments. Finally, educate system administrators about the risk of sensitive data exposure in logs and encourage secure logging practices.