Worked on the pennlabs/penn-clubs repository to enhance security for user-generated HTML content across Club Applications, Fairs, and Imported Events. Addressed a critical XSS vulnerability by implementing robust HTML sanitization, introducing new validation methods and a dedicated cleaning utility to ensure all user-provided HTML is safe before rendering. Leveraged Python and Django to integrate these security measures directly into the backend, aligning with best practices for web application security. This update reduced the attack surface for member-facing features and improved content integrity, demonstrating a focused approach to backend development and security within a collaborative, production-grade codebase.