An OS command injection vulnerability in Flowise versions prior to 3.0.1 allows unauthenticated attackers to execute arbitrary system commands.

The Custom MCPs feature executes OS commands without adequate validation or authentication, allowing an unauthenticated remote attacker to trigger command execution via the application.

With a CVSS score of 9.8, this vulnerability allows an attacker to achieve Remote Code Execution (RCE) on the underlying host. This provides the attacker the ability to install persistent backdoors, steal sensitive credentials, or move laterally within the network, leading to a complete compromise of the affected environment.

Immediate Action: Update Flowise to version 3.0.1 or later immediately to remediate the command injection flaw.

Proactive Monitoring: Monitor server process execution logs for the spawning of unexpected child processes or command-line activity originating from the Flowise service.

Compensating Controls: Deploy a Web Application Firewall (WAF) with rules configured to detect and block suspicious OS command injection patterns in incoming requests.

Public Exploit Available: Yes, a Metasploit module and detection templates exist.

This vulnerability is highly critical due to the ease of RCE and the existence of public exploitation modules. Organizations must prioritize the update to version 3.0.1 and ensure that the Flowise instance is not exposed to the public internet without additional authentication layers.