Cursor Security Audit: Complete Guide for Founders

In May 2026, we scanned a Cursor-built SaaS platform handling real customer data. The app looked polished. The onboarding flow worked. Stripe was integrated. The founder had shipped fast — exactly what Cursor is designed for. The Launch Readiness Score came back at 61/100.

The top finding: the /api/auth/login endpoint had no rate limiting. Zero. Our scanner sent 10,000 requests in under 60 seconds and the server responded to every single one. A credential-stuffing attack — where an attacker cycles through a list of known email/password pairs stolen from other breaches — could run undetected, indefinitely, until a real user got locked out of their own account.

This is not a Cursor problem. Cursor is an exceptional tool — the fastest path from idea to deployed product that exists right now. The problem is that security controls do not generate themselves. Cursor generates code. It does not generate a threat model. It does not configure rate limiting middleware. It does not enable Supabase Row Level Security on your tables. It does not inject HTTP security headers into your server responses. These are decisions that sit outside the code-generation loop — and most founders do not know they are missing until something goes wrong.

This guide covers the five most common vulnerability classes we see in Cursor-built apps, how each one manifests in generated code, what the real-world risk is, and exactly what to do to fix it. At the end, there is a free tool that runs the entire audit in under two minutes.

What Cursor Does (And Doesn't) Secure by Default

Cursor is an AI-powered IDE, not a security framework. Understanding that distinction precisely is the first step to shipping a safe product.

What Cursor does well: it generates structurally correct code, follows common library conventions, and produces patterns that work. When you ask it to build an authentication system using a popular library like NextAuth or Supabase Auth, it generates code that authenticates users correctly. The login flow works. Sessions persist. Passwords are hashed. These functional correctness properties are solid.

What Cursor does not do is harden that code against adversarial conditions. There is a significant difference between code that works for legitimate users and code that holds up against an attacker. The distinction shows up in four areas consistently:

Rate limiting is an infrastructure concern, not an application concern. Cursor generates application-layer code. Whether your server applies a request rate limit before that code runs depends on your hosting configuration, your middleware stack, or an API gateway rule. Cursor does not configure those. It does not know whether you are deploying to Vercel, Railway, or a bare EC2 instance. It does not add rate limiting middleware unless you explicitly ask for it — and even then, the configuration needs to be tested.

HTTP security headers require server-level configuration. Headers like Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security are set by the web server or a framework middleware layer, not by application logic. Cursor will generate a Next.js app. It will not automatically add a next.config.js headers block that configures CSP. That step is invisible unless you know to look for it.

Database access control defaults are permissive. Supabase ships with Row Level Security disabled by default on new tables. Cursor-generated code that creates a table and queries it will work — but unless RLS is explicitly enabled and policies are written, any authenticated user can query any row in that table. Cursor writes the queries. It does not write the policies.

Secrets appear in source code during development and can stay there. Cursor assists with code that references environment variables, but during rapid prototyping it is common to hardcode API keys temporarily. Those keys end up in git history, in bundled JavaScript files, or in committed .env files. Cursor does not scan for secrets or warn you when a key appears where it should not.

None of this means Cursor-built apps are inherently unsafe. It means they require a deliberate security pass before they handle production data. The rest of this guide shows you exactly what that pass needs to cover.

Top 5 Vulnerability Classes in Cursor-Built Apps

These figures come from our scan dataset across apps submitted to Launch Ready Code's State of Vibe Code Security report, June 2026. The percentages reflect the share of Cursor-built apps where each issue was detected.

// app/api/auth/login/route.ts
export async function POST(req: Request) {
  const { email, password } = await req.json();
  const user = await db.users.findUnique({ where: { email } });
  if (!user || !await bcrypt.compare(password, user.passwordHash)) {
    return Response.json({ error: 'Invalid credentials' }, { status: 401 });
  }
  // ⚠ No rate limiting — 10,000 requests/min accepted silently
  return Response.json({ token: await createSession(user.id) });
}

// next.config.js — missing from most Cursor-generated projects
const securityHeaders = [
  { key: 'X-Frame-Options',        value: 'DENY' },
  { key: 'X-Content-Type-Options',  value: 'nosniff' },
  { key: 'Referrer-Policy',         value: 'strict-origin-when-cross-origin' },
  { key: 'Strict-Transport-Security',value: 'max-age=63072000; includeSubDomains' },
  { key: 'Content-Security-Policy',  value: "default-src 'self'; script-src 'self'" },
];

-- Supabase default state after Cursor-generated table creation
CREATE TABLE user_documents (
  id        uuid DEFAULT gen_random_uuid() PRIMARY KEY,
  user_id   uuid REFERENCES auth.users(id),
  content   text,
  created_at timestamptz DEFAULT now()
);
-- ⚠ RLS not enabled. Any authenticated user can SELECT * FROM user_documents.

// components/AiFeature.tsx — visible in the JS bundle
const openai = new OpenAI({
  apiKey: process.env.NEXT_PUBLIC_OPENAI_KEY, // ⚠ shipped to every browser
  dangerouslyAllowBrowser: true,
});
// This key is now in your compiled bundle at /_next/static/chunks/...

// server.ts — Cursor-generated Express setup
import cors from 'cors';

app.use(cors({
  origin: '*',          // ⚠ allows any origin — never on auth routes
  credentials: true,   // ⚠ credentials: true + wildcard = cross-origin theft
}));

app.post('/api/auth/token', issueToken); // now accessible from any site

Security Comparison: Cursor vs Lovable vs Bolt

Cursor is not alone in leaving these controls unconfigured. Lovable and Bolt share the same gaps — because all three tools are code generators, not security platforms. The table below reflects our scan data across all three tools as of June 2026.

The pattern is consistent: every AI code generator leaves security configuration as a manual step. The difference between a safe app and a vulnerable one is whether the founder knows those steps exist.

How a URL-Based Security Audit Works

The standard assumption about security audits is that they require code access — you hand over your repository, someone reads through it for two weeks, and you get a report. That model works for enterprise security reviews. It does not work for a founder who shipped last week and needs to know if they are safe today.

A URL-based security audit works differently. It inspects your running application — the same surface an attacker would target — and surfaces what is detectable without ever touching your source code.

Here is what our scanner checks from a URL alone. When you submit your app's URL to Launch Ready Code, our agent makes a series of controlled HTTP requests to your domain, your API endpoints, and any subdomains it can discover. It inspects every response header to check for the presence and correct configuration of CSP, HSTS, X-Frame-Options, and other security headers. It probes authentication endpoints for rate limiting by sending calibrated request sequences and measuring response patterns. It checks whether your JavaScript bundles contain strings matching known API key formats — OpenAI keys, Stripe keys, AWS access keys, and others. It tests CORS policy by sending requests from synthetic attacker origins and observing the Access-Control-Allow-Origin response.

What it cannot check from a URL: your database RLS configuration (that requires a database query), internal business logic errors, or vulnerabilities that only manifest after authentication with a specific user role. The audit covers your external attack surface — which is where 73% of real-world exploits start.

The result is a scored report across four dimensions — Security, Reliability, Performance, and Monitoring — delivered in under two minutes. The free tier returns your overall score. The full Launch Readiness Audit Report at $499 returns every finding with severity, file reference where detectable, recommended fix, and a prioritized remediation roadmap. No code access. No onboarding call. No waiting period.

How to Fix Each Vulnerability Class

Real Finding: Cursor SaaS Scanned May 2026

This is not an unusual case. The 61/100 score is close to the median for Cursor-built apps in our dataset. The vulnerabilities were not caused by bad engineering decisions — they were caused by gaps between what Cursor generates and what production security requires. Closing those gaps took this founder less than a week.

Frequently Asked Questions