CVE-2025-53949 is an OS command injection vulnerability classified under CWE-78, affecting Fortinet FortiSandbox versions 4.0.x through 5.0.2. FortiSandbox is a security appliance designed to detect and analyze advanced threats by executing suspicious files in a controlled environment. The vulnerability arises from improper neutralization of special elements in HTTP requests processed by the FortiSandbox management interface. An attacker with authenticated access and high privileges can craft malicious HTTP requests that inject operating system commands, leading to unauthorized code execution on the underlying system. This can allow attackers to gain control over the FortiSandbox appliance, potentially compromising the security monitoring infrastructure and pivoting to other internal systems. The CVSS v3.1 base score of 7.0 reflects network exploitability (AV:N), low attack complexity (AC:L), but requiring high privileges (PR:H) and no user interaction (UI:N). The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), indicating full compromise potential. Although no exploits are currently known in the wild, the vulnerability's characteristics make it a significant risk, especially in environments where FortiSandbox is deployed as a critical security layer. The lack of publicly available patches at the time of disclosure necessitates immediate risk mitigation through access controls and monitoring until updates are released.

For European organizations, the exploitation of CVE-2025-53949 could lead to complete compromise of FortiSandbox appliances, undermining their ability to detect and analyze advanced threats. This could result in attackers evading detection, deploying malware, or moving laterally within networks. Confidential data processed or stored on these systems could be exposed or altered, and availability of sandboxing services could be disrupted, affecting incident response capabilities. Organizations in sectors such as finance, telecommunications, government, and critical infrastructure that rely heavily on Fortinet products for security monitoring are particularly vulnerable. The breach of FortiSandbox could also facilitate supply chain attacks or targeted espionage campaigns. Given the appliance’s role in security operations, the impact extends beyond a single system to the broader security posture of affected organizations.

1. Immediately restrict administrative access to FortiSandbox management interfaces to trusted personnel and networks using network segmentation and firewall rules. 2. Implement multi-factor authentication (MFA) for all administrative accounts to reduce risk from credential compromise. 3. Monitor HTTP request logs for unusual or malformed requests targeting FortiSandbox interfaces, focusing on indicators of command injection attempts. 4. Apply vendor patches or updates as soon as they become available; coordinate with Fortinet support for early access or workarounds. 5. Conduct regular vulnerability assessments and penetration tests on FortiSandbox deployments to detect potential exploitation attempts. 6. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics tuned to detect exploitation patterns related to this vulnerability. 7. Maintain up-to-date backups of FortiSandbox configurations and data to enable rapid recovery in case of compromise. 8. Educate security teams about this vulnerability and ensure incident response plans include scenarios involving FortiSandbox compromise.