Broken Authentication in Lovable Apps
Lovable generates authentication flows using Supabase Auth, but the AI frequently implements authorization checks only on the client side. Attackers bypass these checks entirely by calling the Supabase API directly.
Scan Your Lovable AppHow It Happens
Lovable typically sets up Supabase Auth for login and signup, which works correctly for authentication (verifying who the user is). The problem is authorization (controlling what the user can do). Lovable's AI places access checks in React components using conditional rendering: if the user isn't an admin, hide the admin panel. This is purely cosmetic. The underlying Supabase queries that power the admin panel are still callable by anyone with a valid session token. An attacker who creates a regular account can call the same Supabase RPC functions or query the same tables that the admin panel uses. Another common pattern is Lovable storing user roles in a profiles table without RLS, allowing any authenticated user to change their own role to "admin" by updating the row directly through the Supabase REST API.
Impact
Broken authentication lets regular users escalate to admin privileges. In a SaaS app built with Lovable, this means accessing other users' data, modifying billing, or deleting accounts. Attackers can also create multiple accounts freely since Lovable rarely implements rate limiting on signup. Combined with client-side-only authorization, this allows automated abuse of any feature the app exposes. For apps that handle payments, broken auth can lead to unauthorized refunds, coupon abuse, or accessing premium features without paying.
How to Detect
Create a regular (non-admin) account and use the browser's network tab to capture the Supabase API calls that admin pages make. Then replay those calls using a tool like curl or Postman with your regular user's access token. If the calls succeed, authorization is broken. Check whether the user roles table has RLS enabled. Query it directly with the anon key to see if you can read or modify roles. Vibe App Scanner tests for client-side-only auth checks by probing API endpoints with different permission levels and checking for proper server-side enforcement.
How to Fix
Move all authorization checks to Supabase RLS policies. Instead of hiding UI elements, ensure the database itself rejects unauthorized operations. An admin-only table should have a policy like: USING ((select auth.uid()) IN (SELECT user_id FROM admins)). Use Supabase custom claims or the profiles table with RLS to manage roles. Never trust role information that comes from the client. Implement rate limiting on authentication endpoints using Supabase Edge Functions or a reverse proxy. Limit signup attempts per IP and add email verification before granting access. For sensitive operations, implement Supabase RPC functions with SECURITY DEFINER that perform their own authorization checks server-side, rather than relying on client-side logic.
Code Examples
Admin authorization check
// Client-side only check - easily bypassed
function AdminPanel() {
const { user } = useAuth()
if (user?.role !== 'admin') return <Redirect to="/" />
return <AdminDashboard />
}-- Server-side RLS policy on admin_data table
CREATE POLICY "Only admins can access"
ON admin_data FOR ALL
TO authenticated
USING (
(select auth.uid()) IN (
SELECT user_id FROM user_roles
WHERE role = 'admin'
)
);Frequently Asked Questions
Is Supabase Auth itself insecure?
No. Supabase Auth handles authentication (login/signup) securely. The issue is that Lovable's generated code often implements authorization (access control) only in the UI, which attackers can bypass by calling the API directly.
How do I add proper admin controls to a Lovable app?
Create a user_roles table with RLS that only allows admins to modify roles. Write RLS policies on admin-only tables that check the user's role. Never rely on client-side checks alone.
Can attackers create admin accounts in my Lovable app?
If the roles table lacks RLS, yes. An attacker can sign up for a regular account, then update their own role to admin by calling the Supabase REST API directly. Always protect the roles table with RLS policies.
Related Security Resources
Is Your App Vulnerable?
VAS automatically scans for broken authentication and other security issues in Lovable apps. Get actionable results with step-by-step fixes.
Scans from $5, results in minutes.