What are the most common Vercel security mistakes?

The most common mistake is not adding security headers, particularly Content-Security-Policy, which leaves the application vulnerable to cross-site scripting attacks. Developers frequently expose secrets through NEXT_PUBLIC_ environment variables or by committing .env files to public repositories. Leaving preview deployments publicly accessible exposes unreleased features and staging data to anyone with the URL. Many applications also lack rate limiting on API routes, making them vulnerable to brute-force attacks and abuse. UNPWNED detects all of these common issues and provides specific fix instructions for each vulnerability found in your Vercel deployment.