Critical XSS Vulnerability in FortiSandbox Allows Unauthenticated Command Execution
Fortinet has recently disclosed a significant security vulnerability in its FortiSandbox platform, identified as CVE-2025-52436 (FG-IR-25-093). This high-severity cross-site scripting (XSS) flaw enables unauthenticated attackers to execute arbitrary commands on affected systems, posing a substantial risk to organizations utilizing this security solution.
Understanding the Vulnerability
The vulnerability is classified as an Improper Neutralization of Input During Web Page Generation issue, commonly referred to as CWE-79. It resides within the graphical user interface (GUI) component of FortiSandbox and has been assigned a CVSS score of 7.9, indicating a high level of severity.
At its core, this reflected XSS vulnerability stems from inadequate input sanitization during web page generation. An attacker can craft malicious requests—often by manipulating parameters or utilizing the browser’s back button—to inject executable JavaScript into the GUI. When a victim, such as an administrator, interacts with the compromised page, the injected script executes, potentially escalating to remote code execution (RCE). This escalation grants the attacker full command-line access to the system, leading to possible data exfiltration, lateral movement within the network, or evasion of sandbox mechanisms designed to analyze malware.
Impacted Versions and Recommended Actions
The vulnerability primarily affects FortiSandbox Platform-as-a-Service (PaaS) deployments. The specific versions impacted and the corresponding recommended actions are as follows:
| Version Series | Affected Builds | Recommended Action |
|—————-|———————–|————————–|
| 5.0 | 5.0.0 to 5.0.1 | Upgrade to 5.0.2 or later|
| 4.4 | 4.4.0 to 4.4.7 | Upgrade to 4.4.8 or later|
| 4.2 | All versions | Migrate to a fixed release|
| 4.0 | All versions | Migrate to a fixed release|
Fortinet has released patches in PaaS versions 4.4.8 and 5.0.5 to address this vulnerability. The company strongly urges all users to upgrade to these versions immediately to mitigate potential risks. In the interim, Fortinet recommends implementing network segmentation and restricting GUI access to minimize exposure until the systems are fully patched.
Discovery and Implications
The vulnerability was internally discovered by Jaguar Perlas of Fortinet’s Burnaby Infosec team. This incident highlights the persistent threat posed by XSS vulnerabilities in enterprise tools, including those designed to isolate and analyze potential threats like FortiSandbox.
Organizations that rely on FortiSandbox for malware scanning or handling sensitive information should prioritize patching their systems promptly. Unpatched systems are susceptible to exploitation, which could lead to unauthorized command execution and further compromise of network security.
As of the latest reports, there is no known exploitation of this vulnerability in the wild. However, the unauthenticated nature of the attack vector necessitates heightened vigilance and immediate action to secure affected systems.
Conclusion
The disclosure of CVE-2025-52436 serves as a critical reminder of the importance of regular system updates and vigilant security practices. Organizations utilizing FortiSandbox should act swiftly to apply the necessary patches and review their security protocols to prevent potential exploitation.
