Bolt.new Security Guide: 7 Vulnerabilities to Fix Before Launch

Quick answer: Bolt.new apps often ship with critical flaws like API keys bundled in client JavaScript and missing Supabase RLS policies. To secure your app, move secrets to server-side functions, scope RLS to auth.uid(), and enforce server-side authentication. SimplyScan finds these vulnerabilities in 30 seconds, helping you ship safely.

By Paula C · Kraftwire Software

To secure a Bolt.new app, you must move all secret API keys to server-side Edge Functions, enforce Row-Level Security (RLS) policies scoped to auth.uid() on every Supabase table, and implement server-side authentication guards on all protected routes. Bolt.new prioritizes speed over security, often bundling sensitive credentials into client-side JavaScript and leaving database tables open to unauthorized access.

Why Do Bolt.new Apps Need a Security Audit?

Describe your idea, and Bolt generates a full-stack app running in a WebContainer · right in your browser. No local setup, no deployment pipeline, just instant results. However, this "vibe-coding" speed creates a significant security gap.

Bolt.new apps are particularly susceptible because the AI optimizes for a functional UI rather than a secure architecture. Because Bolt handles everything from package installation to deployment, many developers never review the raw code, leading to "silent" vulnerabilities that are only discovered after an attacker drains an API balance or leaks a database.

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The 7 Critical Bolt.new Vulnerabilities

1. API Keys Bundled in Client-Side JavaScript

This is the most frequent high-severity issue. When you prompt Bolt to "integrate OpenAI" or "connect to Stripe," it often places the secret key directly in a React component or a utils/api.ts file. Since Bolt apps are client-side by default, that key is bundled into the JavaScript sent to every visitor.

The Danger:

• Financial Drain: An exposed OpenAI or Anthropic key can be used by bots to rack up thousands of dollars in charges in hours.
• Data Breach: A Supabase service_role key allows an attacker to bypass all RLS and download your entire database.
• Domain Hijacking: Exposed SendGrid or Mailgun keys allow attackers to send spam or phishing emails from your verified domain.

How to Fix It:

• Move all secrets to server-side Edge Functions or API routes.
• Use only publishable keys (like the Supabase anon key) in the frontend.
• If a secret was ever committed to your repository or deployed, rotate it immediately.
• Use SimplyScan to automatically detect exposed keys in your deployed bundle.

2. Missing or Weak Row-Level Security (RLS)

Bolt often enables RLS on Supabase tables because the boilerplate requires it, but it frequently fails to write the specific policies needed to protect data.

Common RLS Failures:

• The "Authenticated" Trap: Policies that allow access if auth.role() = 'authenticated'. This allows *any* logged-in user to read *every* other user's data.
• Missing Policies: Tables with RLS "on" but no policies effectively block all access, leading frustrated developers to disable RLS entirely just to "make it work."
• Update/Delete Neglect: Developers often secure SELECT but forget to restrict who can UPDATE or DELETE rows.

How to Fix It:

• Every policy must be scoped to the user: USING (auth.uid() = user_id).
• Use the SimplyScan RLS guide to audit your table permissions.
• Test by creating two different accounts and attempting to access Account A's data from Account B's session.

3. Broken Access Control on Protected Routes

Bolt builds beautiful dashboards fast, but it rarely adds the middleware or guards required to keep them private. If you ask for an "Admin Panel," Bolt may build the route /admin but fail to check if the user is actually an admin before rendering the data.

The Risk:

An attacker doesn't need to "hack" your site; they just need to guess the URL. Once there, they can view sensitive business metrics, user lists, or configuration settings.

How to Fix It:

• Implement a centralized ProtectedRoute component.
• Verify authentication on the server side (Edge Functions or Middleware) rather than just checking a local state variable.
• Audit your routes using an application security checklist.

4. Exposed Service-Role Keys and Connection Strings

While the Supabase anon key is safe for the frontend, Bolt sometimes accidentally includes the service_role key or the full PostgreSQL connection string (postgres://...) in the environment variables bundled for the browser.

The Danger:

The service_role key is the "God Mode" of your database. It ignores all RLS policies. If this key is in your frontend, your database is effectively public.

How to Fix It:

• Search your codebase for service_role and postgresql://.
• Ensure these are only used in server-side environments.
• Use SimplyScan's secret scanner to verify your production bundle is clean.

5. Vulnerable or Malicious Dependencies

Bolt.new installs npm packages automatically based on the AI's suggestions. Sometimes the AI suggests outdated packages with known CVEs, or worse, it might hallucinate a package name that leads to a typosquatting attack.

How to Fix It:

• Run npm audit in your Bolt terminal regularly.
• Keep your dependencies lean; if Bolt added a library you don't need, remove it.
• Check for vulnerable dependencies before every major deployment.

6. Client-Side Authorization Logic

A common "vibe-coding" mistake is checking user permissions only in the UI. For example: {user.isAdmin && <DeleteButton />}. While this hides the button, it does nothing to stop an attacker from calling the delete API endpoint directly.

The Danger:

Client-side code is under the user's control. Anyone can open DevTools, change a React state variable from isAdmin: false to isAdmin: true, and reveal hidden UI elements.

How to Fix It:

• Treat the frontend as a "suggestion." The server (API/Database) must be the final authority.
• Enforce roles at the database level using RLS and custom claims.
• Read more on broken access control to understand how to move logic to the server.

7. Missing Security Headers (CSP, HSTS, XFO)

Bolt apps deployed to Vercel or Netlify often lack the headers that protect users from Cross-Site Scripting (XSS) and Clickjacking.

Essential Headers:

• Content-Security-Policy (CSP): Prevents unauthorized scripts from running.
• Strict-Transport-Security (HSTS): Forces HTTPS connections.
• X-Frame-Options: Prevents your site from being embedded in a malicious iframe.

How to Fix It:

• Add a vercel.json or _headers file to your project.
• Use the SimplyScan CSP generator to create a strict policy.
• Verify your headers with our security headers tool.

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The Ultimate Vibe-Coding Security Checklist

Before you share your Bolt.new URL on social media, run through this checklist:

• Secrets: Are all sk- keys and service_role keys removed from the frontend?
• Database: Is RLS enabled on *every* table with a auth.uid() check?
• Auth: Do protected routes redirect unauthenticated users to /login?
• Logic: Is authorization checked on the server/API, not just the UI?
• Headers: Does the site have a valid CSP and HSTS configuration?
• Audit: Have you run a SimplyScan to find hidden leaks?

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Why Speed and Security Must Coexist

While Bolt.new is fast, a slow or insecure app will ultimately fail to convert users. Security isn't just about preventing hacks; it's about building trust. An app that leaks user data or gets its API keys revoked due to abuse cannot scale.

By spending 30 minutes following this guide, you can turn a "vibe-coded" prototype into a production-ready application.

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Frequently Asked Questions

Is Bolt.new safe for building production apps?

Yes, provided you perform a manual security audit. Bolt.new prioritizes functionality and speed, which often leads to "predictable" vulnerabilities like exposed API keys and missing RLS policies. You must move secrets to the server and verify all database permissions before going live.

Is the Supabase anon key safe to expose in Bolt?

The anon key is designed to be public, but it is only safe if your Row-Level Security (RLS) policies are correctly configured. If RLS is disabled or poorly written, the anon key can be used to steal your entire database. Never expose the service_role key, as it bypasses all security measures.

Why is RLS enabled but my data still feels unprotected?

Bolt often enables RLS by default, but it may not create the specific policies required to restrict data to the owner. A common mistake is using a policy that allows access to any "authenticated" user. You must ensure every policy includes a check like auth.uid() = user_id to prevent users from seeing each other's data.

How do I check my Bolt.new app for exposed API keys?

You can manually inspect your production JavaScript bundles using browser DevTools (Sources tab) and searching for strings like sk- or Bearer. However, a faster method is using SimplyScan, which automatically scans your deployed site for exposed secrets, environment variables, and sensitive configuration files in about 30 seconds.

Does checking user.role === 'admin' in React protect my app?

No. Client-side checks are for user experience only. An attacker can easily bypass these checks by modifying the application state in their browser or by sending requests directly to your API. All authorization must be enforced on the server side or at the database level using RLS policies.

How long does it take to secure a Bolt.new app?

Securing a standard Bolt.new app typically takes 30 to 60 minutes. The process involves moving secrets to server-side functions, writing RLS policies for your tables, and adding security headers. Using a tool like SimplyScan can reduce this time by instantly identifying the exact files and lines where vulnerabilities exist.