This environment is for local, isolated testing only. Do not expose this instance to the public internet or any untrusted network. Keep it on a private, local-only network segment and separate from production systems. Use at your own risk.

Verify the Vulnerability (Proof of Concept)

Once the container is running, you can access the n8n interface at http://localhost:5678. To test the vulnerability, you will inject a malicious JavaScript payload into an expression field. Steps to Reproduce:

1. Log in: Access the dashboard (if you set up basic auth, use the credentials provided; otherwise, create a new owner account).
2. Create Workflow: Click "Add Workflow" or navigate to https://n8n.example.com/workflow/new.
3. Add Node: Add a "Set" node.
4. Inject Payload: In the "Value" field of the Set node (ensure you toggle "Expression" mode if available, or simply paste the syntax which n8n interprets as an expression), input one of the following payloads: Test 1: Environment Variable Exfiltration This payload attempts to access the process environment variables, which often contain secrets.

Test 2: Remote Code Execution (RCE) This payload attempts to load the child_process module to run system commands (e.g., whoami).

Expected Result: If the environment is vulnerable, the "Output" panel of the Set node will display the result of the command (e.g., root or the n8n user) or a JSON object containing the environment variables. If the instance were patched (e.g., version 1.122.0+), the sandbox would return an empty object or an error.