The kernel is the core of an operating system. It controls memory, schedules processes, and talks to hardware while running with the highest system privileges. Because every user process depends on it, the kernel is the trust boundary between ordinary applications and the rest of the machine.
In cyber security, kernel bugs are especially dangerous because they can turn a low-privilege action into full system control. If the kernel mishandles memory ownership, permissions, or input from the network stack, an attacker may escape user-space limits and reach root-level access. Defenders focus on patching, reducing exposed kernel features, and limiting risky capabilities such as unprivileged user namespaces or unused networking modules. In practice, kernel security is about making sure that the most powerful code on the system never trusts data or ownership assumptions it has not verified.