Skip to content

README.md

Latest commit

 

History

History
186 lines (143 loc) · 8.02 KB

README.md

File metadata and controls

186 lines (143 loc) · 8.02 KB

n8n Vulnerable Sandbox (Ni8mare & Others)

Overview

This repository provides a robust template for creating a local, vulnerable n8n sandbox. It is designed for Red Teaming, allowing you to study and reproduce Ni8mare (CVE-2026-21858) and other critical vulnerabilities in a safe, isolated container.

Using as a Sandbox Template

This project serves as a "Vulnerable n8n Instance". It runs a specific version of n8n that contains a critical security flaw, configured to be exploitable for educational and testing purposes.

Why use this for Red Teaming?

  • Controlled Environment: Test attacks and defenses in a safe, isolated container without risking production systems.
  • Reproducibility: Guarantee the exact version (1.65.0) and configuration needed to trigger the vulnerability.
  • Offline Capable: Work in air-gapped or restricted network environments.
  • Zero Risk: Isolate RCE payloads within a disposable container volume.

The template includes the vulnerable application, automated setup using Make, and container orchestration using Podman.

Architecture

Production Deployment (Target Architecture)

In a real-world scenario, n8n is often deployed behind a load balancer or reverse proxy, processing webhooks and user interactions that trigger workflows.

graph TB
    subgraph "Client Environment"
        User[User / Webhook Source]
    end
    
    subgraph "Production Infrastructure"
        LB[Load Balancer / Nginx]
        n8n[n8n Instance]
        DB[(Database)]
    end
    
    subgraph "External Services"
        APIs[Third-party APIs]
        S3[Cloud Storage]
    end
    
    User -->|HTTPS| LB
    LB -->|HTTP| n8n
    n8n --> DB
    n8n -->|API Requests| APIs
    n8n -->|File Mode| S3
    
    style User fill:#e1f5ff
    style LB fill:#fff4e1
    style n8n fill:#fff4e1
    style DB fill:#ffe1f5
    style APIs fill:#ffe1f5
Loading

Local Sandbox Setup (This Template)

This sandbox simplifies the architecture to focus purely on the vulnerability, exposing the n8n instance directly to the host machine.

graph LR
    subgraph "Client Environment"
        Attacker[UI or Script]
    end
    
    subgraph "Vulnerable Environment (Container)"
        n8n_cont["n8n Instance (v1.120.0)<br/>:5678"]
        Engine[Node Engine]
        FS[Container File System<br/>/home/node/.n8n]
    end
    
    Attacker -->|"HTTP Request"| n8n_cont
    n8n_cont --> Engine
    Engine -->|"Arbitrary File Write"| FS
    FS -->|"Execute Code"| Engine
    Engine -->|"Response"| n8n_cont
    n8n_cont -->|"Response"| Attacker
    
    style Attacker fill:#e1f5ff
    style n8n_cont fill:#fff4e1
    style Engine fill:#fff4e1
    style FS fill:#ffe1f5
Loading

Vulnerabilities

n8n has disclosed four critical vulnerabilities, in January 2026, that affect the n8n instance running in this sandbox (version 1.120.0):

ID Title Nickname Description
CVE-2025-68613 Remote Code Execution via Dynamic Code Resources - A flaw in the handling of dynamic code resources that permits authenticated users to achieve remote code execution (RCE).
CVE-2025-68668 Sandbox Escape via Workflow Manipulation N8scape Allows authenticated users with workflow privileges to bypass the sandbox and execute arbitrary commands on the host system.
CVE-2026-21877 Unrestricted File Upload leading to RCE - An unrestricted file upload vulnerability that enables authenticated attackers to execute malicious code and compromise the instance.
CVE-2026-21858 Unauthenticated RCE via Form-based Workflows Ni8mare A critical unauthenticated RCE where attackers leverage form-based workflows to access server files and gain full control.

Prerequisites

  • Podman (or Docker – replace podman with docker in the Makefile if desired)
  • Make (for running automation commands)

Configuration

Vulnerability Configuration

The sandbox is configured via Makefile environment variables to ensure exploitability across the different CVEs.

Note: If these variables are not explicitly set in your environment, the Makefile ensures they are passed to the container at runtime.

1. NODES_EXCLUDE=""

  • Effect: Explicitly enables all nodes, including dangerous ones like Execute Command and Read/Write Files that might otherwise be restricted.
  • Relevance to CVEs:
    • CVE-2025-68668 (N8scape): Directly facilitates this by ensuring the Code node and others are available to attempt sandbox escapes.
    • CVE-2026-21877: Ensures nodes required for post-exploitation (like file writing or command execution) are available once access is gained.
    • CVE-2026-21858 (Ni8mare): While this is an auth bypass/form issue, having all nodes enabled ensures that any malicious workflow payload can execute without restriction.

2. N8N_HOST=0.0.0.0

  • Effect: Exposes the service to the entire network (binding to all interfaces).
  • Relevance to CVEs:
    • All CVEs: Increases the attack surface by making the instance reachable from external networks (or the host), simulating a misconfigured production deployment.

3. WEBHOOK_URL=http://localhost:5678/

  • Effect: Sets the base URL for webhooks.
  • Relevance to CVEs:
    • CVE-2026-21858 (Ni8mare): This exploit relies on form-based triggers. Correct webhook URL configuration ensures that the form URLs generated by n8n are reachable and valid for the attacker to query.

Data Persistence

  • Volume: ./data is mounted to /home/node/.n8n to persist workflows and credentials between restarts.

Quick Start

# View all available commands
make help

# Full setup and launch
make n8n

The vulnerable n8n interface will be available at http://localhost:5678.

Available Commands

Run make help to see all commands:

Main:

  • make n8n - Full setup: clean, build, and start n8n.

Container Operations:

  • make build - Build the container image.
  • make up - Run the container.
  • make down - Stop and remove the container.
  • make clean - Clean up containers, images, and networks.
  • make logs - Follow container logs.

Testing the Vulnerability

  1. Start the Sandbox: make n8n
  2. Access UI: Visit http://localhost:5678.
  3. Setup: You may need to create an owner account on first launch.
  4. Exploit attempt:
    • Create a workflow.
    • Add an "Execute Command" node (enabled by our config).
    • Or attempt the specific Arbitrary File Write payload associated with CVE-2026-21877.

Project Structure

.
├── data/                     # Persisted n8n data (workflows, credentials)
├── Containerfile            # Podman container definition
├── Makefile                 # Developer and automation commands
└── README.md                # This file

Troubleshooting

Port conflicts:

  • If port 5678 is in use: make clean to remove old containers or check other running services.

Container issues:

  • View logs: make logs
  • Restart: make down && make up
  • Full cleanup: make clean && make build && make up

References