Claude Code auth

CORS Wildcard Allow-Origin Too Permissive

CORS configured with Access-Control-Allow-Origin: * allowing any origin to access the API. Security audit flags this as a vulnerability. Any website can make requests to the API on behalf of users.

While allowing all origins is convenient for development, it's a security risk in production.

Error Messages You Might See

Security audit: CORS wildcard origin OAuth token vulnerability from CORS misconfiguration CSRF risk from overly permissive CORS
Security audit: CORS wildcard originOAuth token vulnerability from CORS misconfigurationCSRF risk from overly permissive CORS

Common Causes

  1. Wildcard used for simplicity during development and never changed for production
  2. CORS allowed for all endpoints including sensitive ones
  3. Misunderstanding that wildcard is safe (it's not)
  4. No authentication on API endpoints, relying on origin restriction
  5. CORS configured globally without considering security implications

How to Fix It

Replace * with specific domains: Access-Control-Allow-Origin: https://trusted.example.com. For multiple domains: check Origin header, return specific domain if in whitelist. Only allow CORS for non-sensitive endpoints. Sensitive operations (delete, payment) should require stronger auth. Always combine with authentication (JWT tokens), don't rely on origin alone.

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Frequently Asked Questions

Why is Access-Control-Allow-Origin: * unsafe?

Any website can make authenticated requests on user's behalf. If user logged in, attacker's site can call API as that user.

How to allow multiple specific origins?

Check Origin header. If in whitelist, return it: Access-Control-Allow-Origin: origin (where origin is the value sent).

Should sensitive APIs allow CORS?

No. CORS should only apply to read-only or public APIs. Sensitive operations (delete, payment) should require stronger auth.

Related Claude Code Issues

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