CVE-2025-15313 is a vulnerability identified in Tanium EUSS (Endpoint User State Store) versions 1.17.0 and 1.18.0, classified as an improper link resolution before file access, commonly referred to as a 'link following' vulnerability. This flaw allows an authenticated user with low privileges to exploit the way the software resolves symbolic or hard links before performing file operations, specifically file deletion. By manipulating link resolution, an attacker can cause the system to delete arbitrary files that the user should not have permission to remove, thereby compromising system integrity. The vulnerability does not impact confidentiality or availability directly but can lead to significant integrity issues by removing critical files. The CVSS v3.1 base score is 5.5 (medium severity), reflecting the local attack vector (AV:L), low attack complexity (AC:L), low privileges required (PR:L), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), high integrity impact (I:H), and no availability impact (A:N). There are no known public exploits or active exploitation campaigns reported to date. Tanium, a widely used endpoint management and security platform, is often deployed in enterprise environments for asset management, patching, and threat detection, making this vulnerability relevant for organizations relying on these versions. The vulnerability was reserved at the end of 2025 and published in early 2026, indicating a recent discovery and disclosure. The lack of patch links suggests that remediation may be pending or available through vendor support channels.

For European organizations, the primary impact of CVE-2025-15313 lies in the potential unauthorized deletion of files by low-privileged authenticated users within Tanium EUSS environments. This can disrupt endpoint management operations, lead to loss of critical configuration or state files, and potentially degrade security monitoring and response capabilities. Organizations in sectors with stringent regulatory requirements for data integrity, such as finance, healthcare, and critical infrastructure, may face compliance risks if such file deletions affect audit logs or security controls. Although the vulnerability does not allow remote exploitation or direct data exfiltration, insider threats or compromised low-privilege accounts could leverage this flaw to sabotage systems or evade detection. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially in environments where Tanium EUSS is widely deployed. Disruption to endpoint security functions could indirectly increase exposure to other cyber threats. Therefore, European enterprises using affected Tanium versions should consider this vulnerability a moderate risk to operational integrity and security posture.

To mitigate CVE-2025-15313, European organizations should first verify their Tanium EUSS version and prioritize upgrading to a patched version once officially released by Tanium. Until patches are applied, organizations should enforce strict access controls limiting Tanium EUSS usage to trusted administrators and service accounts, minimizing the number of users with low privileges who can interact with the system. Implementing robust monitoring and alerting for unusual file deletion activities or changes in critical directories related to Tanium operations can help detect exploitation attempts early. Network segmentation and endpoint protection measures should be enhanced to reduce the risk of lateral movement by attackers who gain low-privilege access. Additionally, organizations should review and harden file system permissions to prevent unauthorized link manipulation and consider application whitelisting to restrict execution of unauthorized scripts or commands that could exploit this vulnerability. Engaging with Tanium support for guidance and timely patch deployment is essential. Finally, conducting internal audits and penetration testing focused on link resolution and file access controls can help identify and remediate related weaknesses.