External risk intelligence

FortiSIEM Command Injection Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2025-25256

FortiSIEM is a centralized management appliance designed for network-wide visibility. Because it requires broad connectivity and handles sensitive infrastructure data, it is frequently exposed to network access. This vulnerability allows unauthenticated remote command injection via crafted CLI requests, making exposed instances highly attractive targets for exploitation.

OS Command Injection

Fortinet Fortisiem

5.4.0 to before 6.7.107.0.0 to before 7.0.47.1.0 to before 7.1.87.2.0 to before 7.2.67.3.0 to before 7.3.2

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in Fortinet's FortiSIEM product, affecting a wide range of versions. This issue allows an unauthenticated attacker to execute unauthorized commands, potentially leading to significant compromise of the system. The main concern is confirming if our environment utilizes the affected technology and understanding the potential exposure.

Attackers can run unauthorized commands on affected systems.
It impacts a critical security monitoring and management tool.
Confirm relevance and potential exposure to this critical flaw.

Attack Path

How an attacker could exploit the issue

An attacker can target Fortinet FortiSIEM by sending specially crafted commands over the network. If successful, this allows the attacker to run unauthorized code or commands on the affected system.

No authentication required.
Triggered via crafted CLI requests.
Allows unauthorized code execution.

Live Threat

Current exploitation, exposure, and threat context

An improper neutralization of special elements used in an OS command vulnerability could allow an unauthenticated attacker to execute unauthorized code or commands via crafted CLI requests when supported by the advisory. This could affect the integrity and availability of the affected system.

System data could be compromised.
Crafted CLI requests could cause execution.
Unauthorized code execution may occur.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Fortinet FortiSIEM product is a security information and event management solution, suggesting that ownership likely resides with the Security Operations (SecOps) or Security Engineering teams responsible for managing it, alongside the Infrastructure or Platform teams that host and maintain the appliance. The initial action is to locate all deployed instances of FortiSIEM, assess their network exposure and criticality, identify the specific system owner for each, and then develop a prioritized remediation plan.

Security and Infrastructure teams own this.
Verify instance exposure and criticality first.
Plan remediation and vendor coordination.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is FortiSIEM?

FortiSIEM is a security information and event management platform. It aggregates data from across a network to provide unified visibility, helping organizations monitor logs, detect threats, and manage infrastructure health. Because it centralizes logs and security events, it often requires extensive network connectivity to communicate with diverse assets throughout an environment.

What is the vulnerability in CVE-2025-25256?

CVE-2025-25256 is an OS command injection vulnerability, classified as CWE-78. This means the system fails to properly filter special characters in user-provided input. An attacker can exploit this weakness to inject and run their own unauthorized commands directly on the underlying operating system of the FortiSIEM appliance, bypassing standard application security controls.

How is this FortiSIEM vulnerability triggered?

The vulnerability is triggered when an attacker sends crafted CLI requests to the appliance. No authentication is needed to initiate this process, meaning the attacker does not need to log in to the system. Legitimate, non-crafted requests or administrative actions performed through standard interfaces do not trigger this command injection.

Is my FortiSIEM instance at risk?

Halo Surface Signal indicates that FortiSIEM instances are frequently network-exposed due to their need for broad data collection. If your instance is reachable from the internet, it is a high-priority target for this flaw. Even if internal, any attacker who gains a foothold on your network may be able to reach and exploit the management appliance.

What are the first steps to address this issue?

Begin by identifying all deployed versions of FortiSIEM within your environment to see if they fall into the affected ranges listed in the advisory. Once identified, consult the official vendor guidance to determine the appropriate update or mitigation path. Coordinate with your infrastructure and security teams to prioritize patching or restricting network access for these appliances.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.