A USB controller is the hardware layer that manages communication between a computer and its USB devices. It sits between the operating system and the ports, translating USB traffic so keyboards, drives, adapters, and other peripherals can work. Modern systems often use controller families such as xHCI, which newer operating systems understand better than older ones.
In cyber security, the USB controller matters because it controls a trusted interface to removable media and input devices. Attackers may abuse USB for malware delivery, data theft, or device impersonation, while defenders rely on controller support for device control, logging, and port restriction. In compatibility problems, an older OS may fail to communicate with a newer controller, leaving hardware unusable unless the right drivers or firmware support exist. That makes USB controller compatibility a practical issue for both secure deployment and legacy system maintenance.