Audit n8n instance security with the n8n API, api.n8n.io and GitHub advisories

Description

Quick overview
This workflow runs every morning to audit your n8n instance, compare its version against n8n GitHub security advisories with branch-aware patch detection, and email a scored report and fix plan via SMTP when new risks are found or on a weekly digest.

How it works
Runs daily at 07:00 (or manually for testing) and loads instance-specific settings like the n8n URL and optional version override.
Calls your n8n instance’s /api/v1/audit endpoint using an X-N8N-API-KEY header to retrieve the built-in security audit report.
Fetches the official stable n8n versions list from api.n8n.io to help determine the instance version when the audit doesn’t report missing updates.
Pulls published security advisories for n8n-io/n8n from the GitHub Security Advisories API.
Analyzes the audit and advisories to detect your effective n8n version, flag advisories affecting that version (including backport-aware patch matching), identify audit findings (including workflows broken by disabled nodes policy), and compute a risk score, grade, trend, and ordered fix plan.
Sends a plain-text email report via SMTP when there are new urgent issues, when a check fails (reported as SKIPPED, never a fake all-clear), on the weekly report day, or when always-send testing is enabled.

Setup
Create an n8n API key with “Instance operations” scope and add an HTTP Header Auth credential that sends X-N8N-API-KEY to your N8N_URL.
Set N8N_URL in the Set Sentinel Settings node to the base URL your n8n instance can reach (for example http://localhost:5678) and optionally set VERSION_OVERRIDE if you run a beta/next build.
Add an SMTP credential and update the “to” and “from” email addresses in the email step.
(Optional) Set WEEKLY_REPORT_DAY and ALWAYS_SEND in the Set Sentinel Settings node to control weekly digests and testing behavior, then run a manual execution to validate email delivery before activating the schedule.

Requirements
Self-hosted n8n with the public API enabled (tested on n8n 2.41.7)
n8n API key with the "Instance operations" scope
SMTP credential for the email report
Outbound access to api.n8n.io and api.github.com (no keys needed)

Customization
Change the schedule in the "Every Morning at 7am" trigger
Set WEEKLY_REPORT_DAY in the Set Sentinel Settings node (0 = Sunday … 6 = Saturday, empty = off)
Adjust score weights and grade thresholds in the Score Risk and Build Report node
Replace Send Report Email with Slack, Telegram or any other node (use subject and report_text)

Additional info
Branch-aware matching: n8n backports security fixes to older version lines (for example 2.41.4 for 2.41.x). A plain version comparison would wrongly flag those instances as vulnerable; Sentinel counts a fix on your own major.minor line as patched. The fix plan is rule-based, not AI-generated. "New since last run" and the 30-run trend are kept in workflow static data, which n8n saves only in scheduled (production) runs. Each run reads the 100 most recent n8n security advisories from GitHub.