CVE-2024-46663 is a stack-buffer overflow vulnerability identified in Fortinet FortiMail's command-line interface (CLI) affecting versions 7.6.0 through 7.6.1 and earlier versions before 7.4.3. The flaw arises due to improper handling of input in the CLI, allowing a privileged attacker with local access to send specially crafted commands that overflow a stack buffer. This overflow can be leveraged to execute arbitrary code or commands with elevated privileges, potentially leading to full system compromise. The vulnerability requires the attacker to have high-level privileges on the device, meaning it is not exploitable remotely without prior access. The CVSS v3.1 base score is 6.5, reflecting medium severity, with high impact on confidentiality, integrity, and availability. The attack vector is local (AV:L), attack complexity is low (AC:L), privileges required are high (PR:H), and no user interaction is needed (UI:N). The scope is unchanged (S:U), and the exploitability is functional (E:F). No public exploits or active exploitation have been reported yet. FortiMail is a widely deployed email security gateway product used globally in enterprises to protect email infrastructure from spam, malware, and targeted attacks. This vulnerability could allow attackers who have already gained privileged access to escalate their control, bypassing security controls and potentially compromising sensitive email data or disrupting email services.

The impact of CVE-2024-46663 is significant for organizations using Fortinet FortiMail appliances, as exploitation allows an attacker with existing privileged access to execute arbitrary code, potentially leading to full system compromise. This can result in unauthorized access to sensitive email data, disruption of email services, and lateral movement within the network. The confidentiality, integrity, and availability of the affected systems are all at risk. Although remote exploitation is not possible without prior access, the vulnerability increases the risk posed by insider threats or attackers who have already breached perimeter defenses. Organizations relying on FortiMail for email security may face operational disruptions and data breaches if this vulnerability is exploited. The absence of known exploits in the wild provides a window for mitigation, but the presence of a functional exploitability rating indicates that exploitation is feasible once access is obtained.

To mitigate CVE-2024-46663, organizations should prioritize applying vendor patches or updates as soon as they become available for affected FortiMail versions. Until patches are released, restrict CLI access strictly to trusted administrators and enforce strong authentication and access controls to minimize the risk of privilege escalation. Implement network segmentation to limit access to FortiMail management interfaces and monitor logs for unusual CLI command activity indicative of exploitation attempts. Employ endpoint detection and response (EDR) solutions to detect anomalous behavior on FortiMail devices. Regularly audit user privileges and remove unnecessary administrative rights to reduce the attack surface. Additionally, consider deploying multi-factor authentication (MFA) for CLI access and ensure that backup and recovery procedures are in place to restore services in case of compromise. Finally, maintain up-to-date threat intelligence to respond promptly if exploit code becomes publicly available.