CVE-2025-25251 is a high-severity local privilege escalation vulnerability affecting Fortinet's FortiClient for Mac versions 7.0.0 through 7.0.14, 7.2.0 through 7.2.8, and 7.4.0 through 7.4.2. The vulnerability stems from an Incorrect Authorization issue (CWE-863) in the handling of XPC (interprocess communication) messages. Specifically, a local attacker with limited privileges can craft malicious XPC messages to the FortiClientMac application, which improperly authorizes these requests, allowing the attacker to escalate their privileges on the affected system. The CVSS v3.1 base score of 7.4 reflects the vulnerability's high impact on confidentiality, integrity, and availability, with an attack vector limited to local access but requiring low complexity and no user interaction. The vulnerability does not require user interaction but does require the attacker to have some level of local access (low privileges). Exploitation could lead to full system compromise, enabling attackers to execute arbitrary code with elevated privileges, access sensitive data, or disrupt system operations. Although no known exploits are currently reported in the wild, the presence of a public CVE and detailed technical information increases the risk of future exploitation. Fortinet has not yet published patches or mitigation details, emphasizing the need for proactive defensive measures. The vulnerability affects multiple major versions of FortiClientMac, indicating a broad impact across organizations using this VPN and endpoint security client on macOS platforms.

For European organizations, this vulnerability poses a significant risk, especially those relying on FortiClientMac for secure remote access and endpoint protection. Successful exploitation could allow attackers to bypass security controls, gain administrative privileges, and move laterally within corporate networks. This could lead to data breaches involving sensitive personal data protected under GDPR, intellectual property theft, disruption of business operations, and potential regulatory penalties. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly at risk due to the sensitive nature of their data and the strategic importance of their operations. The local attack vector means that attackers would need initial access to the endpoint, which could be achieved through phishing, physical access, or other initial compromise methods. Once local access is obtained, this vulnerability could be leveraged to escalate privileges and deepen the compromise. Given the widespread use of Fortinet products in Europe and the increasing reliance on Mac endpoints in enterprise environments, the vulnerability could have broad implications if exploited at scale.

European organizations should implement the following specific mitigation strategies: 1) Immediately inventory and identify all macOS endpoints running affected FortiClient versions (7.0.x, 7.2.x, 7.4.x). 2) Monitor Fortinet’s official channels for patches or updates addressing CVE-2025-25251 and prioritize rapid deployment once available. 3) Until patches are released, restrict local access to endpoints by enforcing strict physical security and endpoint access controls, including disabling unnecessary local accounts and enforcing strong authentication. 4) Employ endpoint detection and response (EDR) solutions capable of detecting anomalous interprocess communication or privilege escalation attempts on macOS. 5) Implement application whitelisting and macOS system integrity protections to limit the ability of malicious processes to execute or escalate privileges. 6) Educate users on the risks of local compromise vectors such as phishing or social engineering that could lead to initial local access. 7) Conduct regular audits of endpoint security configurations and privilege assignments to minimize the attack surface. 8) Consider network segmentation and zero-trust principles to limit lateral movement from compromised endpoints. These measures, combined with timely patching, will reduce the likelihood and impact of exploitation.