v0 Security Audit: What to Check Before You Launch Your v0 App

What is Understanding v0: What It Builds and What It Skips?

Launch Ready Code benchmark: across the 700+ apps we've scanned, the average Launch Readiness Score is ~44/100 — most ship with at least one critical finding. — LRC scan data, 2026

Launch Ready Code has scanned 700+ applications. Most ship with at least one critical finding, and the average Launch Readiness Score is ~44 out of 100 — LRC scan data, 2026.

v0 by Vercel is a prompt-driven UI generator. You describe a component or page, and v0 produces clean Next.js React code with Tailwind styling. It is fast, it produces readable output, and it integrates directly into your project. That is exactly what it should do.

The security problem is not what v0 does. It is what v0 does not do. v0 generates the display layer. It assumes that the data feeding your components is already secured. It assumes that the API routes handling form submissions are protected. It assumes that the environment variables it references are correctly scoped. None of those assumptions are checked. None of those protections are added.

When you move fast with v0 and ship what it builds without a security review, you are shipping those assumptions as facts. That is where the gaps come from.

What is NEXT_PUBLIC_ Trap: How v0 Apps Leak Secrets?

This is the most common v0 security mistake we see. v0 generates code that references environment variables. When you wire those up, it is easy to use NEXT_PUBLIC_ for convenience. That prefix tells Next.js to bundle the variable into the client-side JavaScript — which means every visitor can read it in the page source.

This is CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). If your Stripe key, OpenAI key, Supabase service role key, or any other secret ends up with NEXT_PUBLIC_, it is public. It ships to every browser that loads your app.

The fix is straightforward. Use NEXT_PUBLIC_ only for values you are comfortable showing any visitor (your app name, a public feature flag). All secrets go in server-side environment variables, accessed only through API routes (/api/*) that validate user identity before returning any data.

// Wrong - key goes to the browser
const key = process.env.NEXT_PUBLIC_STRIPE_SECRET_KEY;

// Correct - stays server-side only
// In /api/checkout.ts:
const key = process.env.STRIPE_SECRET_KEY; // No NEXT_PUBLIC_ prefix

Our guide to finding exposed secrets in AI app bundles shows how to scan your production build for leaked keys. Our guide to securing API keys in AI-built apps covers the move-to-server pattern in detail.

What should you know about dangerouslySetInnerHTML and XSS Risk?

v0 sometimes uses dangerouslySetInnerHTML to render content quickly. This is a primary vector for CAPEC-63 (Cross-Site Scripting). If your app accepts user input and renders it through dangerouslySetInnerHTML without sanitization, an attacker can inject malicious scripts that execute in other users' browsers.

This maps to OWASP A03:2021 (Injection). Every use of dangerouslySetInnerHTML that touches user-provided content needs a sanitization library (DOMPurify is the standard) before it can ship.

Search your v0-generated codebase for every instance of dangerouslySetInnerHTML. If any of them render data that comes from user input, a database, or an external API, add sanitization before launch.

What is Missing Server-Side Protection: CSRF, Auth, and Rate Limiting?

v0 generates forms and UI components. It does not generate the server-side middleware that protects the API routes those forms call.

What should you know about CSRF Protection?

Without CSRF tokens, state-changing routes accept cross-origin requests without validating the origin. An attacker can craft a request that triggers a logged-in user's browser to execute an action on their behalf — CAPEC-62 (Cross-Site Request Forgery), CWE-352. This is OWASP A01:2021 (Broken Access Control) at the route level. Add CSRF token validation to all POST, PUT, and DELETE routes before launch.

What should you know about Authentication Middleware?

v0 builds login forms. It does not enforce auth on the API routes behind those forms. A page that looks like it requires login might serve data to any unauthenticated request if the API route itself does not check the session. This is CWE-862 (Missing Authorization). Test every protected route by calling it directly — logged out, in a fresh browser session. If it returns data, it is unprotected.

What should you know about Rate Limiting?

Auth endpoints, password resets, and any AI inference route need rate limiting. Without it, a bot can make unlimited requests — brute-forcing passwords, hammering your OpenAI endpoint, or running up your usage costs. This is CWE-307 (Improper Restriction of Excessive Authentication Attempts), OWASP A07:2021. Use a middleware package (express-rate-limit, Vercel's built-in rate limiting, or Upstash for edge routes) before launch.

What is Row Level Security: The Database Gap v0 Leaves Open?

If your v0 app connects to Supabase, the same RLS gap that affects Lovable, Bolt, and Cursor apps affects yours too. v0 generates database queries and UI to display the results. It does not enable Row Level Security on your tables.

With RLS off, your public Supabase anon key (which is in your client-side code) can read every row in every table. CVE-2025-48757 (CVSS 9.3) documented 170+ apps exposed this way. The fix: enable RLS on every table, write owner-scoped policies in SQL, and test with the anon key to confirm access is denied on protected data.

Our Supabase RLS guide covers the SQL and the testing steps. The CVE-2025-48757" target="_blank" rel="noopener">NIST NVD entry for CVE-2025-48757 scores the RLS-off class at CVSS 9.3 (Critical).

What is OWASP Coverage: What a v0 Security Audit Checks?

A v0 security audit covers all four dimensions we scan: security, reliability, performance, and monitoring. The security findings map to the OWASP Top 10:

• A01:2021 Broken Access Control — Missing auth middleware on API routes, RLS disabled, unprotected admin endpoints (CWE-284, CWE-862).
• A02:2021 Cryptographic Failures — NEXT_PUBLIC_ secrets bundled to the client (CWE-200). Service role or Stripe keys readable in page source.
• A03:2021 Injection — dangerouslySetInnerHTML with unsanitized user input (CWE-79). XSS vectors in rendered content.
• A05:2021 Security Misconfiguration — Missing CSP, HSTS, X-Frame-Options, X-Content-Type-Options headers.
• A07:2021 Identification and Authentication Failures — No rate limiting on auth and AI endpoints (CWE-307). No CSRF protection on state-changing routes (CWE-352).

The CISA Secure by Design principles call for eliminating entire classes of vulnerability by default — the same gaps v0 leaves for developers to close manually.

How does v0 compare to Lovable and Bolt: Who Owns Security?

v0 gives you more control than Lovable or Bolt because you own the deployment. That also means you own every security gap the platform does not close for you. See our AI coding platform security comparison for the full breakdown across all eight platforms.

What should you know about Pre-Launch v0 Security Checklist?

1. No NEXT_PUBLIC_ on secret keys. Grep your codebase: grep -r "NEXT_PUBLIC_" ./. Any secret key with that prefix is public. Move it server-side.
2. Sanitize all dangerouslySetInnerHTML. Every instance that renders external or user data needs DOMPurify or equivalent before launch.
3. CSRF tokens on all state-changing routes. POST, PUT, DELETE routes should validate the origin or use CSRF tokens.
4. Auth middleware on every protected API route. Test each protected route in an unauthenticated session. It should return 401.
5. RLS enabled on every Supabase table. Owner-scoped policies. Test with the anon key to confirm access is denied.
6. Rate limiting on /api/auth, /api/reset, and AI routes. Use Vercel's built-in rate limiting or a middleware package.
7. Security headers set. Configure next.config.js to add CSP, HSTS, X-Frame-Options, X-Content-Type-Options.
8. Error tracking live. Add Sentry or equivalent before launch. Break something on purpose and confirm an alert fires.
9. Run the URL scan. launchreadycode.com/free-scan. It checks your live app from the outside, where the above gaps show up in practice.

What should you know about From Free Scan to Full Audit?

The free scan takes 30 seconds and gives you a Launch Readiness Score out of 100. It tells you where the most urgent gaps are.

The Launch Readiness Audit Report ($499, one-time) covers all four dimensions in depth: security, reliability, performance, and monitoring. It includes a benchmark against 200+ audited apps, a prioritized fix roadmap with time estimates per issue, and senior review of every finding. This is not something v0 provides — it is the external check your app needs before real users depend on it.

Want ongoing coverage? Our subscription tiers (from $149/mo) run daily scans. New gaps are surfaced the day they appear. Our Code Care tier assigns a human Fractional CTO who reviews and ships every fix.

Frequently Asked Questions