RDP USB redirection is a Remote Desktop feature that makes USB devices plugged into the client appear inside the remote session as if they were attached to the server. This is useful for printers, smart cards, storage, and specialized hardware, because admins can support remote work without physically moving devices.
From a security perspective, redirection matters because it extends the trust boundary. The remote host must process device descriptors, class drivers, and installation logic based on input coming from a remote endpoint. If that handling is weak, attackers may abuse it to trigger unexpected driver loading, device installation, or privilege escalation paths. Defenders reduce risk by limiting which device classes can be redirected, monitoring policy settings, and treating redirected USB traffic as a controlled attack surface rather than a simple convenience feature.