Security Issues in v0 Code

v0 components themselves are generally safe since they're pure UI. The security risks come when integrating them: form components that submit to unvalidated endpoints, data displayed without proper sanitization, and authentication UI that isn't connected to a real auth system (fake login forms that accept any credentials)

Connect auth UI to a real authentication provider. Add server-side validation for all form submissions. Sanitize any user-generated content before rendering. Implement proper authorization checks before showing sensitive data. Don't trust client-side role checks — verify on the server

Every v0 app needs authentication — verifying who the user is — and authorization — verifying what they're allowed to do. Check that every API route and server action verifies the user's identity before processing requests. Check that users can only access their own data. A common v0 pattern is adding auth to the UI but not the API, which means anyone with the endpoint URL can access data directly.

Never trust data coming from the client. Every form submission, URL parameter, and API request body should be validated server-side before processing. Use a schema validation library like Zod to define expected shapes and reject anything that doesn't match. This prevents injection attacks, data corruption, and unexpected crashes.

Configure security headers to protect against common web attacks: Content-Security-Policy to prevent XSS, Strict-Transport-Security to enforce HTTPS, X-Frame-Options to prevent clickjacking, and X-Content-Type-Options to prevent MIME sniffing. Most hosting platforms let you configure these in a headers file or configuration.

If your app handles user data, processes payments, or stores sensitive information, a professional security review is essential before launch. Our security scan ($19) checks for the most critical vulnerabilities, and our full security review service provides a comprehensive assessment with remediation guidance.