An MMU, or Memory Management Unit, is hardware that helps the CPU translate and control memory access. It can map virtual memory to physical memory, enforce access permissions, and keep one process from freely reading or overwriting another process’s memory.
In cyber security, the MMU is a major isolation layer. Strong memory protection helps limit the impact of bugs, crashes, and some exploits, because an attacker who compromises one process may still be blocked from touching kernel memory or other applications. Systems without an MMU, such as some embedded platforms running -nommu Linux, can still function, but they often have weaker process separation and less forgiving memory safety. Defenders care about this when assessing attack surface, sandboxing, and hardening on constrained or legacy hardware.