Cross-Origin Resource Sharing (CORS) Policy Enforcement in Spring Boot: Security Implications and Best Practices

Cross-Origin Resource Sharing (CORS) is an important function for securing cross-origin requests in web applications between server and client. A cross-origin request is when a web application sends an HTTP request to a different domain, protocol, or port than the one that hosted the original web page. Cross-origin requests typically occur when a client from one domain tries to access resources (such as APIs, images, or other data) across a different domain. Incorrect and broken CORS configurations could influence the security of the application. This work investigates CORS policy enforcement in Spring Boot applications focusing on security considerations and performance concerns. It clarifies common configuration mishaps, such as the embracement of all sources with credentials, and threats associated with them. This research also looks into the preflight OPTIONS request performance effect, especially in authentication-heavy contexts. In addition, it shows how misconfigurations may expose security weaknesses like cross-site request forgery (CSRF) and data exposure, and quantify the performance overhead of CORS checks. The outcome of the work gives advice for securing Spring Boot applications at minimal performance cost and demonstrates that cautious configuration to avoid security and performance bottlenecks is vital.