The 5G core is the central control plane of a 5G mobile network. It handles subscriber authentication, mobility management, policy decisions, and session setup so devices can register, stay connected, and move between cells without dropping service. Unlike the radio link, the core decides whether a device or network function should be trusted and what network resources it may use.
In cyber security, the 5G core matters because weaknesses here can affect many users at once. A flaw in signaling validation or state handling may let an attacker disrupt registrations, force denial of service, or interfere with an active session. Real-world defenses focus on mutual authentication, strict authorization, segmentation of internal interfaces, and careful validation of protocol messages and session state. Because 5G cores are built on interconnected service functions, even a small trust error can cascade through the network if internal traffic is assumed to be safe.