CVE-2025-8943: Flowiseai Flowise RCE Vulnerability

CVE-2025-8943 Overview

CVE-2025-8943 is a critical Remote Code Execution (RCE) vulnerability affecting Flowise, an open-source low-code AI workflow tool. The vulnerability exists in the Custom MCPs (Model Context Protocol) feature, which is designed to execute operating system commands using tools like npx to spin up local MCP Servers. Due to Flowise's minimal authentication and authorization model combined with the lack of role-based access controls (RBAC), and the fact that versions prior to 3.0.1 operate without authentication by default, unauthenticated network attackers can execute unsandboxed OS commands on vulnerable systems.

Critical Impact

Unauthenticated attackers can achieve full system compromise by executing arbitrary OS commands on Flowise instances exposed to the network, leading to complete confidentiality, integrity, and availability compromise.

Affected Products

• Flowise versions prior to 3.0.1
• FlowiseAI Flowise installations with default configurations
• Flowise instances without explicitly configured authentication

Discovery Timeline

• August 14, 2025 - CVE-2025-8943 published to NVD
• September 23, 2025 - Last updated in NVD database

Technical Details for CVE-2025-8943

Vulnerability Analysis

This vulnerability is classified under CWE-306 (Missing Authentication for Critical Function). The core issue stems from the Custom MCPs feature's ability to execute OS commands without proper authentication gates. When Flowise is deployed with default settings (no authentication configured), any network-accessible attacker can leverage this feature to run arbitrary system commands with the privileges of the Flowise process.

The exploitation path is particularly dangerous because the command execution is unsandboxed, meaning there are no restrictions on what commands can be executed or what resources can be accessed. This design flaw, combined with the default-insecure configuration, creates a trivially exploitable attack surface.

Root Cause

The root cause is twofold: First, the Custom MCPs feature inherently requires OS command execution capabilities to function (e.g., running npx commands). Second, Flowise versions before 3.0.1 do not enforce authentication by default, and the platform lacks any form of role-based access control to restrict who can utilize dangerous features like Custom MCPs. This combination of a powerful feature with inadequate access controls creates a critical security gap.

Attack Vector

The attack is network-based and requires no authentication, user interaction, or special privileges. An attacker simply needs network access to a vulnerable Flowise instance. The attack flow involves:

1. Identifying a Flowise instance exposed to the network (potentially via Shodan or similar reconnaissance)
2. Accessing the Custom MCPs feature endpoint without authentication
3. Crafting a malicious request that leverages the MCP command execution functionality
4. Executing arbitrary OS commands with the privileges of the Flowise service account

The vulnerability allows attackers to achieve arbitrary command execution through the MCP feature's command execution interface. Since the commands run unsandboxed, attackers can install backdoors, exfiltrate data, pivot to internal networks, or completely compromise the host system. For detailed technical analysis, refer to the JFrog Security Vulnerability Report.

Detection Methods for CVE-2025-8943

Indicators of Compromise

• Unexpected outbound network connections from the Flowise process
• Unusual child processes spawned by the Flowise Node.js process (e.g., shells, system utilities)
• Suspicious command patterns in system logs originating from the Flowise service user
• New files or executables created in the Flowise working directory or temp directories
• Modified system configurations or new user accounts created around the time of potential exploitation

Detection Strategies

• Monitor network traffic for unauthenticated requests to Flowise MCP-related API endpoints
• Implement process monitoring to detect anomalous child process creation from Node.js processes
• Review Flowise application logs for unusual MCP execution requests, particularly from external IP addresses
• Deploy endpoint detection solutions to monitor for command injection patterns and shell spawning

Monitoring Recommendations

• Enable comprehensive logging for all Flowise API requests and MCP executions
• Configure alerting for any process execution initiated by the Flowise service account outside normal operational patterns
• Monitor file system integrity in directories accessible to the Flowise process
• Implement network segmentation monitoring to detect lateral movement attempts from compromised Flowise hosts

How to Mitigate CVE-2025-8943

Immediate Actions Required

• Upgrade Flowise to version 3.0.1 or later immediately
• If upgrade is not immediately possible, restrict network access to Flowise instances using firewall rules
• Enable authentication on all Flowise deployments—do not rely on default configurations
• Audit existing Flowise instances for signs of prior compromise before remediation

Patch Information

FlowiseAI has addressed this vulnerability in Flowise version 3.0.1. Organizations should upgrade to this version or later to remediate the vulnerability. The patch introduces proper authentication requirements and access controls for the Custom MCPs feature. Consult the JFrog Security Vulnerability Report for additional technical details regarding the vulnerability and remediation.

Workarounds

• Implement network-level access controls to restrict Flowise access to trusted IP addresses only
• Deploy a reverse proxy with authentication in front of Flowise instances
• Disable the Custom MCPs feature if it is not required for your deployment
• Run Flowise with minimal system privileges to limit the impact of potential exploitation

# Example: Restrict Flowise access using iptables
# Allow access only from trusted management network
iptables -A INPUT -p tcp --dport 3000 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 3000 -j DROP

# Example: Enable authentication environment variables for Flowise
export FLOWISE_USERNAME=admin
export FLOWISE_PASSWORD='<strong-unique-password>'