How to secure a Spark Java client application with OpenID Connect (OIDC) using pac4j
Add OpenID Connect (OIDC) login to a Spark Java application with pac4j: a SecurityFilter on a before filter, callback and logout routes, user profile.
🎯 Vulnerability: OAuth 2.0 / JWT Authentication Bypass
💡 Defense Fix: Strictly verify JWT signatures on the backend, enforce state parameter validation, and reject 'alg: none'.