CVE-2025-27759 is a security vulnerability identified in Fortinet's FortiWeb product, specifically affecting versions 7.6.0 through 7.6.3, 7.4.0 through 7.4.7, 7.2.0 through 7.2.10, and all versions prior to 7.0.10. The vulnerability is classified as an OS command injection (CWE-78), which occurs due to improper neutralization of special elements in operating system commands. This flaw allows an authenticated attacker with privileged access to execute unauthorized code or commands by crafting malicious CLI commands. The vulnerability requires the attacker to have high privileges and authenticated access to the system, meaning it is not exploitable remotely by unauthenticated users. The CVSS v3.1 base score is 6.7, indicating a medium severity level. The vector string (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:H/RL:X/RC:C) shows that the attack vector is local (AV:L), with low attack complexity (AC:L), requiring high privileges (PR:H), no user interaction (UI:N), unchanged scope (S:U), and impacts confidentiality, integrity, and availability to a high degree (C:H/I:H/A:H). The exploitability is marked as functional (E:H), with no known exploits in the wild at the time of publication. The vulnerability stems from the FortiWeb CLI interface, which is used for management and configuration, and the injection of OS commands can lead to full system compromise or unauthorized control over the affected device. FortiWeb is a web application firewall (WAF) widely deployed to protect web applications from attacks, so compromising it could allow attackers to bypass security controls or manipulate traffic.

For European organizations, this vulnerability poses a significant risk, especially for those relying on FortiWeb appliances to secure critical web applications and infrastructure. Successful exploitation could lead to unauthorized command execution, resulting in full compromise of the FortiWeb device. This could allow attackers to disable or alter security policies, intercept or manipulate web traffic, and potentially pivot to other internal systems. The impact on confidentiality, integrity, and availability is high, as attackers could exfiltrate sensitive data, disrupt services, or implant persistent backdoors. Given the high adoption of Fortinet products in Europe, particularly in sectors such as finance, government, and telecommunications, the threat could affect critical infrastructure and sensitive data protection. The requirement for authenticated privileged access somewhat limits the attack surface but insider threats or compromised credentials could enable exploitation. Additionally, the lack of known exploits in the wild currently reduces immediate risk but does not preclude future exploitation attempts. Organizations must consider the potential for targeted attacks leveraging this vulnerability to gain elevated control over their security infrastructure.

To mitigate this vulnerability, European organizations should prioritize the following actions: 1) Apply vendor-provided patches or updates as soon as they become available for the affected FortiWeb versions. Since no patch links are currently provided, organizations should monitor Fortinet advisories closely. 2) Restrict administrative access to FortiWeb devices using strong authentication mechanisms such as multi-factor authentication (MFA) and limit access to trusted personnel only. 3) Implement network segmentation to isolate management interfaces of FortiWeb appliances from general network access, reducing the risk of unauthorized access. 4) Conduct regular audits of privileged accounts and credentials to detect and remediate any compromised or unnecessary accounts. 5) Monitor FortiWeb logs and network traffic for unusual CLI command activity or signs of privilege escalation attempts. 6) Employ intrusion detection and prevention systems to detect anomalous behavior related to FortiWeb management. 7) Educate administrators on secure CLI usage and the risks of executing untrusted commands. 8) Prepare incident response plans specifically addressing potential FortiWeb compromise scenarios to enable rapid containment and recovery.