Security Issues in Codex CLI Code

Codex-generated code commonly uses shell command construction with user input (subprocess injection risk), writes files to paths derived from user input, and skips authentication on any generated API endpoints. It may also generate code that stores credentials in plaintext config files or logs them to stdout

Audit every subprocess call and replace string interpolation with argument arrays. Validate and sanitize any file path derived from external input. Add authentication middleware to every API endpoint. Store credentials in environment variables and load them with os.environ or dotenv. Remove any debug logging that includes sensitive values

Every Codex CLI app needs authentication — verifying who the user is — and authorization — verifying what they're allowed to do. Check that every API route and server action verifies the user's identity before processing requests. Check that users can only access their own data. A common Codex CLI pattern is adding auth to the UI but not the API, which means anyone with the endpoint URL can access data directly.

Never trust data coming from the client. Every form submission, URL parameter, and API request body should be validated server-side before processing. Use a schema validation library like Zod to define expected shapes and reject anything that doesn't match. This prevents injection attacks, data corruption, and unexpected crashes.

Configure security headers to protect against common web attacks: Content-Security-Policy to prevent XSS, Strict-Transport-Security to enforce HTTPS, X-Frame-Options to prevent clickjacking, and X-Content-Type-Options to prevent MIME sniffing. Most hosting platforms let you configure these in a headers file or configuration.

If your app handles user data, processes payments, or stores sensitive information, a professional security review is essential before launch. Our security scan ($19) checks for the most critical vulnerabilities, and our full security review service provides a comprehensive assessment with remediation guidance.