CVE-2025-41656: Node_RED Server RCE Vulnerability

CVE-2025-41656 Overview

CVE-2025-41656 is a critical authentication bypass vulnerability affecting devices running Node-RED servers with default configurations. An unauthenticated remote attacker can execute arbitrary commands on affected devices with high privileges due to missing authentication controls on the Node-RED server interface. This represents a severe security risk as the vulnerability requires no user interaction and can be exploited directly over the network.

Critical Impact

Unauthenticated attackers can achieve complete system compromise with full command execution capabilities, potentially leading to data theft, ransomware deployment, lateral movement, or persistent access to industrial control systems.

Affected Products

• Devices running Node-RED servers with default authentication configurations
• Industrial control systems with exposed Node-RED interfaces
• IoT devices utilizing Node-RED for automation workflows

Discovery Timeline

• 2025-07-01 - CVE CVE-2025-41656 published to NVD
• 2025-07-03 - Last updated in NVD database

Technical Details for CVE-2025-41656

Vulnerability Analysis

This vulnerability is classified under CWE-306 (Missing Authentication for Critical Function). The root issue stems from Node-RED server deployments that do not have authentication configured by default, leaving administrative interfaces and command execution capabilities exposed to any network-accessible attacker.

Node-RED is a flow-based development tool commonly used for wiring together hardware devices, APIs, and online services in IoT and industrial automation environments. When authentication is not properly configured, attackers can access the Node-RED editor interface and inject malicious flows that execute system commands with the privileges of the Node-RED process—typically running with elevated permissions to interact with hardware and system resources.

The attack is network-based and requires no privileges or user interaction to exploit. The scope is changed, meaning successful exploitation can impact resources beyond the vulnerable component itself, potentially compromising the entire host system or enabling lateral movement to other networked devices.

Root Cause

The vulnerability exists because authentication for the Node-RED server is not configured by default. This insecure default configuration allows any network-accessible user to interact with the Node-RED administrative interface without providing credentials. The lack of mandatory authentication enforcement during initial deployment creates an immediate attack surface upon installation.

Attack Vector

Attackers can exploit this vulnerability remotely over the network by:

1. Scanning for exposed Node-RED instances on common ports (typically 1880)
2. Accessing the Node-RED editor interface without authentication
3. Creating or modifying flows to include exec nodes or custom function nodes
4. Executing arbitrary system commands with the privileges of the Node-RED service

The attack leverages Node-RED's built-in functionality for executing system commands, which is intended for legitimate automation purposes but becomes a direct path to system compromise when authentication is absent.

Detection Methods for CVE-2025-41656

Indicators of Compromise

• Unexpected network connections to Node-RED ports (default 1880/TCP) from external IP addresses
• New or modified flows appearing in Node-RED configurations without authorized changes
• Unusual exec node deployments or function nodes containing system command calls
• Process execution chains originating from the Node-RED process (node-red or node)
• Log entries showing flow deployments or API access from unknown sources

Detection Strategies

• Monitor network traffic for unauthenticated access to Node-RED admin endpoints (/flows, /nodes, /settings)
• Implement file integrity monitoring on Node-RED flow configuration files
• Deploy endpoint detection to identify suspicious child processes spawned by Node-RED
• Audit Node-RED access logs for connections from unauthorized IP addresses

Monitoring Recommendations

• Enable and centralize Node-RED access logging for security analysis
• Configure network intrusion detection rules for Node-RED protocol patterns
• Set up alerts for flow deployment events outside of maintenance windows
• Monitor for reconnaissance activity targeting common Node-RED ports across the network

How to Mitigate CVE-2025-41656

Immediate Actions Required

• Enable authentication on all Node-RED instances by configuring adminAuth in the settings file
• Restrict network access to Node-RED interfaces using firewall rules or network segmentation
• Audit existing Node-RED deployments for unauthorized flows or suspicious configurations
• Disable Node-RED services on any systems where they are not required

Patch Information

Refer to the CERT-VDE Security Advisory for vendor-specific guidance and patch information. Organizations should update to firmware or software versions that enforce authentication by default or provide clear deployment guidance for securing Node-RED installations.

Workarounds

• Configure adminAuth in the Node-RED settings.js file to require username and password authentication
• Implement network-level access controls to restrict Node-RED access to trusted IP addresses only
• Place Node-RED instances behind a reverse proxy with authentication enabled
• Use HTTPS to encrypt communications to the Node-RED interface

# Example Node-RED settings.js authentication configuration
# Add the following to your settings.js file

adminAuth: {
    type: "credentials",
    users: [{
        username: "admin",
        password: "$2b$08$HASHED_PASSWORD_HERE",
        permissions: "*"
    }]
}

# Generate password hash using:
# node-red admin hash-pw