CORS for Micronaut

medium4 checks

CORS decides which origins may read your API responses. A wildcard turns an authenticated API into a public one.

What Micronaut must have

  • Access-Control-Allow-Origin limited to known origins
  • No wildcard combined with credentials
  • No reflection of arbitrary Origin headers
  • Preflight responses only allow the methods actually used

How to fix it

  1. 1Replace wildcards with an explicit allowlist
  2. 2Validate Origin before echoing it and reject unknown origins early

Micronaut context

JVM framework with compile-time dependency injection.

Management endpoints default to an internal port; confirm they are not published publicly.