CVE-2024-21762 is a critical security vulnerability identified in Fortinet FortiProxy and FortiOS products, involving an out-of-bounds write flaw that allows remote attackers to execute arbitrary code or commands. This vulnerability affects multiple versions of FortiProxy (from 1.0.0 to 7.4.2) and FortiOS (from 6.0.0 to 7.4.2), covering a broad range of deployed devices. The flaw arises due to improper bounds checking in processing specific crafted network requests, which leads to memory corruption. Exploiting this vulnerability requires no authentication or user interaction, and can be triggered remotely over the network, making it highly accessible to attackers. The CVSS v3.1 base score of 9.6 reflects the critical nature of the vulnerability, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact on confidentiality, integrity, and availability is high, as successful exploitation can lead to full system compromise, data theft, or service disruption. Although no known exploits have been reported in the wild yet, the severity and ease of exploitation make it a prime target for attackers. FortiProxy is widely used in enterprise environments for web proxying, security filtering, and traffic inspection, making this vulnerability particularly dangerous. The vulnerability was reserved in early January 2024 and publicly disclosed in February 2024, with Fortinet expected to release patches. Organizations running affected versions should urgently apply updates or implement mitigations to prevent exploitation.

For European organizations, the impact of CVE-2024-21762 is substantial due to the widespread use of Fortinet FortiProxy appliances in enterprise networks, government agencies, and critical infrastructure sectors. Successful exploitation can lead to unauthorized remote code execution, allowing attackers to gain full control over proxy devices that often handle sensitive traffic and enforce security policies. This can result in data breaches, interception or manipulation of network traffic, disruption of services, and potential lateral movement within networks. The compromise of FortiProxy devices could undermine perimeter defenses, exposing internal systems to further attacks. Given the criticality of these devices in securing internet access and filtering malicious content, the vulnerability poses a direct threat to confidentiality, integrity, and availability of organizational data and services. European organizations in finance, energy, telecommunications, and public administration are particularly at risk due to their reliance on Fortinet products for secure network operations. The lack of required authentication and user interaction lowers the barrier for attackers, increasing the likelihood of exploitation attempts. The absence of known exploits in the wild currently provides a narrow window for proactive defense before active exploitation emerges.

To mitigate CVE-2024-21762, European organizations should immediately identify all FortiProxy and FortiOS devices running affected versions and prioritize patching as soon as Fortinet releases security updates. Until patches are applied, organizations should implement network-level mitigations such as restricting access to FortiProxy management interfaces and service ports to trusted internal networks only, using firewall rules and access control lists. Deploy network intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect and block exploitation attempts. Enable and monitor detailed logging on FortiProxy devices to identify suspicious or anomalous requests that could indicate exploitation attempts. Employ network segmentation to isolate FortiProxy devices from critical internal systems to limit potential lateral movement. Regularly review and update security policies to minimize exposure of FortiProxy services to untrusted networks. Conduct vulnerability scanning and penetration testing focused on FortiProxy appliances to verify the effectiveness of mitigations. Finally, maintain close coordination with Fortinet support and threat intelligence sources for timely updates on exploit developments and patches.