v0 generates real Next.js on real Vercel infra. Here's the env var that leaks to the browser, the service role key, and the server action nobody checks.
A data report on 66 live apps built with Lovable, Bolt, Cursor, base44, and Tempo. 41% of the Supabase-backed apps had at least one table anyone could read with the public anon key. Methodology, findings, and a 60-second self-check.