Is v0 safe? A security guide for v0 apps
v0 (from Vercel) generates Next.js apps, typically App Router with Server Actions and Route Handlers, deployed on Vercel. The polished UI is not the risk. The risk lives in the server code v0 writes: an action or route handler that runs without checking the caller, an environment variable exposed through the NEXT_PUBLIC prefix, or a server-side fetch that can be pointed at internal targets.
The v0 architecture, and where it leaks
Server Actions and Route Handlers are real server endpoints. A generated action that reads or writes data without an authorization check is callable by anyone, whatever the UI shows.
Anything prefixed NEXT_PUBLIC is shipped to the browser. A secret that ends up with that prefix, or a server fetch that forwards a user-supplied URL, is a distinct Next.js failure mode worth checking directly.
What to check on a v0 app
- Every Server Action and Route Handler verifies the session and ownership before it acts.
- No real secret carries the NEXT_PUBLIC prefix; server secrets stay server-side.
- Server-side fetches do not blindly follow a user-supplied URL (SSRF).
- No record returned by supplying another user's ID.
How to check your v0 app
A great-looking app says nothing about whether its actions are guarded. ArgosX exercises the real flows behind the UI, invokes actions and routes as a lower-privileged user, and reports what answers when it should not, with proof and an optional human-verified pass.
Common questions
Does a polished v0 app mean it is secure?
No. The interface quality is separate from whether the Server Actions and Route Handlers behind it check who is calling. A beautiful v0 app can still run a privileged action for any visitor if the authorization check was never added. Test the running app to be sure.
Check your own app for this, free.
A free scan runs in minutes, no signup. Where it finds this, it proves it with the request and screenshot, not just a maybe. A human-verified pass is available when you want a person to confirm every finding.