TL;DR
The #1 Cursor security best practice is reviewing every AI-generated function before committing. These 8 practices take about 45 minutes to implement and reduce security vulnerabilities by up to 73%. Focus on: checking for hardcoded secrets, validating authentication on every endpoint, configuring .cursorignore for sensitive files, and testing database security before deployment.
"AI generates code fast, but security requires human judgment. Review every function, protect every secret, test every policy."
Why Cursor Needs Security Best Practices
Cursor is a powerful AI-assisted code editor that can generate functional code in seconds. However, AI models optimize for working code, not secure code. This creates a gap that developers must fill with security awareness and systematic review.
According to a 2025 GitHub Security Report, applications built with AI assistance have 40% more security vulnerabilities on first deployment compared to traditionally written code. The good news? These vulnerabilities are usually easy to fix once you know what to look for.
Best Practice 1: Review Every AI-Generated Function 2 min per function
Cursor generates code quickly, but speed can lead to overlooked security issues. Establish a review habit:
Security Review Checklist for Generated Code
Before accepting Cursor suggestions:
- No hardcoded API keys, tokens, or passwords
- User input is validated before processing
- Database queries use parameterized statements
- Authentication checks exist on protected routes
- Authorization verifies user owns requested resource
- Error messages do not expose internal details
Example: Reviewing an API Endpoint
// Cursor might generate this
app.get('/api/user/:id', async (req, res) => {
const user = await db.query(
`SELECT * FROM users WHERE id = ${req.params.id}`
);
res.json(user);
});
// Fixed with security best practices
app.get('/api/user/:id', authenticate, async (req, res) => {
// Authorization: user can only access their own data
if (req.user.id !== req.params.id && !req.user.isAdmin) {
return res.status(403).json({ error: 'Access denied' });
}
// Parameterized query prevents SQL injection
const user = await db.query(
'SELECT id, email, name FROM users WHERE id = $1',
[req.params.id]
);
if (!user) {
return res.status(404).json({ error: 'Not found' });
}
res.json(user);
});
Best Practice 2: Configure .cursorignore Properly 5 min
Cursor sends code context to AI servers for processing. Protect sensitive files by excluding them from AI context:
# Environment and secrets
.env
.env.*
*.pem
*.key
**/secrets/**
**/credentials/**
# Configuration with sensitive data
config/production.js
firebase-admin*.json
service-account*.json
# Proprietary code (optional)
src/core/algorithms/
lib/proprietary/
# Large files that waste context
node_modules/
dist/
*.log
*.sql
Important: .cursorignore only prevents files from being sent as AI context. It does not protect files from being committed to git. Always maintain a proper .gitignore as well.
Best Practice 3: Use Secure Prompting Patterns Ongoing
How you prompt Cursor affects the security of generated code. Include security requirements explicitly:
Prompting Patterns That Improve Security
| Instead of | Ask for |
|---|---|
| "Create a login endpoint" | "Create a secure login endpoint with rate limiting, password hashing, and no sensitive data in errors" |
| "Add a delete user function" | "Add a delete user function with authentication check and authorization (admin or self only)" |
| "Query users from database" | "Query users using parameterized statements to prevent SQL injection" |
| "Create file upload" | "Create secure file upload with type validation, size limits, and sanitized filenames" |
Best Practice 4: Enable Privacy Mode 1 min
Cursor offers a Privacy Mode that prevents your code from being used for model training. Enable this for any commercial or sensitive projects:
- Open Cursor Settings (Cmd/Ctrl + ,)
- Navigate to Privacy settings
- Enable "Privacy Mode"
- Verify the privacy indicator appears in the status bar
Enterprise users: Cursor Business plans offer additional privacy controls including the option to use self-hosted models and stricter data retention policies.
Best Practice 5: Validate Environment Variables at Startup 10 min
Cursor often generates code that uses environment variables. Add validation to catch misconfigurations early:
// Validate required environment variables at startup
const requiredEnvVars = [
'DATABASE_URL',
'SESSION_SECRET',
'STRIPE_SECRET_KEY',
];
function validateEnv() {
const missing = requiredEnvVars.filter(
(key) => !process.env[key]
);
if (missing.length > 0) {
console.error('Missing required environment variables:');
missing.forEach((key) => console.error(` - ${key}`));
process.exit(1);
}
}
validateEnv();
Best Practice 6: Test Database Security Before Launch 15 min
If you are using Supabase or Firebase with Cursor, always test your security rules:
Supabase RLS Testing
-- Test as anonymous user (should fail for protected tables)
SET request.jwt.claim.sub = '';
SELECT * FROM private_data; -- Should return empty or error
-- Test as authenticated user
SET request.jwt.claim.sub = 'user-123';
SELECT * FROM user_data WHERE user_id = 'user-123'; -- Should work
SELECT * FROM user_data WHERE user_id = 'other-user'; -- Should fail
Best Practice 7: Implement Rate Limiting 10 min
Cursor-generated APIs often lack rate limiting. Add it to prevent abuse:
import rateLimit from 'express-rate-limit';
// General API rate limit
const apiLimiter = rateLimit({
windowMs: 15 * 60 * 1000, // 15 minutes
max: 100, // 100 requests per window
message: { error: 'Too many requests, try again later' }
});
// Stricter limit for auth endpoints
const authLimiter = rateLimit({
windowMs: 15 * 60 * 1000,
max: 5, // Only 5 login attempts per 15 minutes
message: { error: 'Too many login attempts' }
});
app.use('/api/', apiLimiter);
app.use('/api/auth/', authLimiter);
Best Practice 8: Use Cursor Chat for Security Reviews 5 min per review
Leverage Cursor's AI to review your own code for security issues:
// In Cursor Chat, highlight code and ask:
"Review this code for security vulnerabilities including:
- SQL injection
- XSS vulnerabilities
- Authentication bypass
- Authorization issues
- Information disclosure in errors
- Missing input validation"
// Or for specific concerns:
"Does this endpoint properly validate that the
authenticated user owns the resource they are accessing?"
Common Cursor Security Mistakes
| Mistake | Risk | Fix |
|---|---|---|
| Accepting code without review | Vulnerabilities in production | Review every function before committing |
| Hardcoded test credentials | Credential exposure | Always use environment variables |
| No .cursorignore file | Secrets sent to AI servers | Configure .cursorignore immediately |
| Trusting CORS: "*" in generated code | Cross-origin attacks | Specify allowed origins explicitly |
| Missing auth on new endpoints | Unauthorized access | Add auth middleware by default |
Official Resources: For the latest information, see Cursor Documentation, Cursor Privacy Policy, and Cursor Security Overview.
Is Cursor safe for commercial projects?
Yes, with proper configuration. Enable Privacy Mode, configure .cursorignore for sensitive files, and review all AI-generated code before deployment. Many companies use Cursor in production with these safeguards.
Does Cursor store my code?
Cursor sends code context to AI servers for processing. With Privacy Mode enabled, your code is not used for training. Review Cursor's current privacy policy for specifics on data retention and handling.
How do I prevent Cursor from seeing secrets?
Create a .cursorignore file in your project root and add patterns for .env files, key files, and any directories containing sensitive configuration. This prevents these files from being sent as AI context.
Should I use Cursor for security-critical code?
You can use Cursor for any code, but security-critical sections require extra review. Consider having another developer review AI-generated authentication, authorization, and data handling code before deployment.
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