CVE-2025-57823 is a vulnerability identified in Fortinet's FortiAuthenticator product, specifically affecting versions 6.3.0 through 6.6.6. The flaw arises from a forced browsing issue, where an authenticated user with sponsor-level permissions can directly request and access device log files through specific endpoints without proper authorization checks. Sponsor permissions typically allow limited administrative capabilities, but this vulnerability escalates their ability to read sensitive log data, potentially exposing information about system operations, user activities, or security events. The vulnerability does not require user interaction and can be exploited remotely over the network (AV:N), with low attack complexity (AC:L). However, it requires the attacker to have authenticated access with sponsor privileges (PR:H), limiting the scope of exploitation. The impact is limited to confidentiality (C:L) with no effect on integrity or availability. No known exploits have been reported in the wild, and no patches were linked at the time of disclosure. FortiAuthenticator is widely deployed in enterprise environments for identity management and two-factor authentication, making the exposure of logs a concern for operational security and privacy. The vulnerability's CVSS score of 2.6 reflects its low severity but does not negate the importance of addressing it to prevent information leakage that could facilitate further attacks.

For European organizations, the primary impact of CVE-2025-57823 is the potential unauthorized disclosure of sensitive log data within FortiAuthenticator devices. Logs may contain information about authentication attempts, user identities, system configurations, and security events, which could be leveraged by attackers for reconnaissance or to plan subsequent attacks. Although the vulnerability requires authenticated access with sponsor permissions, insider threats or compromised sponsor accounts could exploit this flaw. Exposure of logs could also violate data protection regulations such as GDPR if personal data is contained within logs. The impact on operational security is moderate, as attackers gaining insight into authentication systems could attempt privilege escalation or lateral movement. However, since the vulnerability does not affect system integrity or availability, direct disruption of services is unlikely. Organizations relying heavily on FortiAuthenticator for critical identity and access management functions should consider this vulnerability a risk to confidentiality and audit integrity.

To mitigate CVE-2025-57823, European organizations should implement the following specific measures: 1) Restrict sponsor-level permissions strictly to trusted personnel and regularly review user roles to minimize the number of accounts with elevated access. 2) Monitor FortiAuthenticator access logs for unusual or unauthorized attempts to access log endpoints, focusing on sponsor accounts. 3) Employ network segmentation and access controls to limit administrative interface exposure to trusted networks and VPNs only. 4) Once Fortinet releases patches or updates addressing this vulnerability, prioritize timely deployment after testing in controlled environments. 5) Consider implementing multi-factor authentication (MFA) for all administrative accounts to reduce the risk of credential compromise. 6) Conduct regular security audits and penetration tests focusing on authentication systems to detect potential abuse of permissions. 7) If possible, disable or restrict access to log download endpoints for sponsor roles until patches are applied. These targeted actions go beyond generic advice by focusing on permission management, monitoring, and access control specific to FortiAuthenticator environments.