During November 2024, Chris Haynes focused on backend development for the cBioPortal/cbioportal repository, addressing a critical API security issue. He improved authentication and authorization handling by reordering the Spring Security filter chains so that the API security chain executes before the OAuth2 filter chain. This adjustment ensures that API requests are authenticated and authorized in the correct sequence, reducing the risk of misrouted authentication flows. The solution was delivered as a single, auditable commit, demonstrating careful attention to maintainability and traceability. Chris utilized Java and Spring Security to implement this fix, reflecting a targeted and thoughtful engineering approach.