Security scanner

Security Scanner for v0 Apps

v0 by Vercel produces polished Next.js apps — but security configuration is not part of the generated output. VibeScan checks your live v0 app for the missing headers, exposed internals, and CORS misconfigurations that need fixing before launch.

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✓ Free  ·  ✓ No login required  ·  ✓ Results in under 60 seconds

89%
of v0 apps have at least one critical issue
< 60s
to get your full report
5 checks
run automatically on every scan
Free
no credit card, no account
Common vulnerabilities

The security issues we find in most v0 apps

v0 generates beautiful, production-quality interfaces fast. But the generated Next.js code often ships without the security headers, server-side validation, and auth middleware your app needs before real users arrive.

Missing security headers not added by v0 or Vercel by default
v0-generated apps deploy to Vercel without a vercel.json headers configuration. This means no Content-Security-Policy, no X-Frame-Options, and no Strict-Transport-Security. Without these, your app is vulnerable to clickjacking, MIME sniffing, and script injection attacks.
API routes returning verbose error details in production
v0-generated API handlers often include try/catch blocks that return the full error object as JSON. In production, this can expose your framework version, database schema, and internal file paths to anyone who triggers an error — which is easy to do intentionally.
Client-side only authentication and authorization
v0 generates UI that hides or shows elements based on auth state. But if the underlying API routes do not verify authentication server-side, the protected data is accessible to anyone who calls the API directly — bypassing the UI entirely.
NEXT_PUBLIC_ environment variables containing sensitive values
v0-generated code sometimes uses NEXT_PUBLIC_ prefixed variables for convenience. Anything prefixed with NEXT_PUBLIC_ is bundled into the client JavaScript and visible to all users. Database URLs, service account IDs, and internal API endpoints should never use this prefix.
Unvalidated redirects in generated navigation code
v0 generates navigation and redirect logic that sometimes uses URL parameters without validation. An attacker can craft a link to your app that redirects users to a phishing site after they log in — a classic open redirect attack.
Exposed API route structure in page source
v0 apps often include the API route structure in client-side code for frontend-backend communication. This gives an attacker a complete map of your endpoints before they start probing for vulnerabilities.
What VibeScan checks

Every scan runs 8 automated checks

VibeScan looks at everything publicly visible in your v0 app — the same things an attacker would look at on day one.

  • ✓HTTPS enforcement — ensures all traffic is encrypted
  • ✓Security headers — X-Frame-Options, CSP, HSTS, X-Content-Type-Options
  • ✓CORS configuration — detects overly permissive origin policies
  • ✓Exposed secrets — scans for API keys and tokens in page source
  • ✓NEXT_PUBLIC_ variable exposure — flags public environment variables with sensitive values
  • ✓Robots.txt analysis — identifies sensitive paths exposed to crawlers
  • ✓JWT and Bearer token detection in client JavaScript
  • ✓Mixed content check — flags HTTP resources on HTTPS pages
Scan your v0 app now

Paste your app URL and get a full security report in under 60 seconds. Free, no signup.

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FAQ

Common questions about v0 security

Does Vercel automatically add security headers for v0 apps?
No. Vercel does not add security headers by default. You need to configure them in vercel.json or in next.config.js using the headers() function. VibeScan checks for these headers and flags which ones are missing.
Is my v0 app secure if I use Vercel Auth?
Vercel Auth handles authentication at the edge and is a solid foundation. But it does not automatically add authorization (who can access what) or protect against CORS issues, exposed secrets, or missing CSP headers. Authentication is one layer — not the whole security story.
How do I add security headers to my v0 app on Vercel?
Create or update your next.config.js to include a headers() function, or add a vercel.json file with a headers array. Specify X-Frame-Options: DENY, X-Content-Type-Options: nosniff, and Strict-Transport-Security: max-age=31536000. VibeScan will verify the headers are live after your next deployment.
What environment variables should I never prefix with NEXT_PUBLIC_?
Never make these public: database connection strings, Stripe secret keys, service account private keys, JWT secrets, admin API tokens, and any key with "secret" or "private" in the name. Only make a variable public if you are comfortable with every user of your app seeing its value.
How is VibeScan different from the Vercel security dashboard?
Vercel's dashboard shows deployment and traffic information. VibeScan actively scans your live app the way an attacker would — checking headers, looking for exposed secrets in page source, and testing CORS policies. They complement each other.

Further reading

The Non-Technical Founder's Guide to Vibe Coding Security →Security Checklist Before Launching Your AI-Generated SaaS →Found Exposed API Keys? Here's What to Do Right Now →

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