CDEX is a desktop environment for Unix-like operating systems in general, and for CusDeb OS in particular. It is based on ReactOS Explorer and is specifically aimed at recreating the classic desktop experience. Unlike other desktop environments for Unix-like operating systems, CDEX is designed to be built in the Portable Executable (PE) binary format and executed using a specialized version of Wine.

The name CDEX is a homage to CDE (Common Desktop Environment), the desktop environment that served as the default graphical environment on Solaris, HP-UX, IBM AIX, Digital UNIX, and UnixWare for many years. CDEX is also an acronym that can be interpreted as either CusDeb Desktop Environment X or Common Desktop Environment X.