An app built primarily with Cursor carries the security posture of whatever code got accepted during AI-assisted edits — Cursor is very good at making code that runs, and has no default mechanism for flagging a hardcoded key, a missing header, or an overly permissive database rule, unless you explicitly prompt it to review for those things.
Cursor accelerates writing and editing code across an entire codebase, which means it can introduce or fail to catch a security gap anywhere in that codebase — not just in newly generated files, but in edits to existing configuration, deploy scripts, or backend rules.
Common issues in Cursor apps
Hardcoded keys accepted during a quick edit
It's easy to accept a suggested edit that hardcodes a key "to get past this error," intending to move it to an environment variable later — and just as easy for that intention to never happen before deploy.
No systematic header or CORS review
Cursor edits the code you point it at. It doesn't proactively audit your deployed headers, CORS policy, or cookie flags unless you ask it to — and most sessions are focused on features, not a security pass.
Backend rules drifting from what the code assumes
As a codebase built with AI-assisted edits grows, it's common for the actual database or API access rules to drift from what the application code assumes is enforced — a gap that only a check against the live, deployed target (not the source code) will catch.