During May 2025, Rui Liu focused on enhancing the robustness and safety of filesystem operations in the tiiuae/nuttx repository. He addressed a critical use-after-free vulnerability in directory rename logic by removing recursive handling and refactoring the directory move path, which improved the reliability of core VFS operations. Working primarily in C, Rui applied his expertise in bug fixing and filesystem development to deliver targeted changes that support safer production deployments. His contributions centered on improving the maintainability and security of directory move operations, demonstrating a thoughtful approach to risk reduction and long-term stability in low-level system code.