CVE-2025-24477 is a heap-based buffer overflow vulnerability identified in multiple versions of Fortinet FortiOS, specifically versions 7.2.4 through 7.2.12, 7.4.0 through 7.4.7, and 7.6.0 through 7.6.2. The flaw exists in the handling of CLI commands, where a specially crafted command can overflow a heap buffer, leading to escalation of privileges. This means an attacker who already has high-level privileges on the device can exploit this vulnerability to gain even greater control, potentially bypassing existing security restrictions. The vulnerability requires local access to the device's CLI and does not require user interaction, but it does require the attacker to have high privileges initially, limiting the attack surface. The CVSS v3.1 score is 4.0 (medium severity), reflecting the limited attack vector (local), the requirement for high privileges, and the potential impact on confidentiality, integrity, and availability, all rated low to medium. No public exploits or active exploitation have been reported as of the publication date. The vulnerability could allow attackers to manipulate device configurations, disrupt network security policies, or gain unauthorized access to sensitive information if exploited successfully. Fortinet has not yet published patches or mitigation details at the time of this report, but the vendor is expected to release updates addressing this issue.

For European organizations, the impact of CVE-2025-24477 can be significant, especially for those relying heavily on Fortinet FortiOS devices for network security, such as firewalls and VPN gateways. Successful exploitation could allow an attacker with existing high privileges to escalate their access, potentially leading to full device compromise. This could result in unauthorized changes to firewall rules, interception or manipulation of network traffic, and disruption of critical security controls. Confidentiality of sensitive data traversing the network could be compromised, and integrity of security policies could be undermined, leading to broader network exposure. Availability could also be affected if attackers disrupt device operations. Given the requirement for local high-privilege access, the threat is more likely to be exploited by insiders or attackers who have already breached perimeter defenses. European sectors with high reliance on Fortinet products, including government, finance, telecommunications, and critical infrastructure, face elevated risks. The absence of known exploits reduces immediate risk but does not eliminate the potential for future attacks once exploit code becomes available.

1. Apply vendor patches promptly once Fortinet releases updates addressing CVE-2025-24477. 2. Restrict CLI access strictly to trusted administrators using secure management protocols and multi-factor authentication. 3. Implement network segmentation to limit access to FortiOS management interfaces, reducing the risk of unauthorized local access. 4. Monitor CLI command logs for unusual or unauthorized commands that could indicate exploitation attempts. 5. Conduct regular audits of user privileges to ensure no unnecessary high-level access is granted. 6. Employ endpoint security controls on devices with CLI access to detect and prevent malicious activity. 7. Use Fortinet’s security advisories and threat intelligence feeds to stay informed about updates and emerging exploit techniques. 8. Consider deploying intrusion detection/prevention systems (IDS/IPS) to detect anomalous traffic patterns related to FortiOS management. 9. Train administrators on secure management practices and awareness of this vulnerability. 10. Prepare incident response plans specifically addressing potential FortiOS compromise scenarios.