GTPv2-C, or GPRS Tunneling Protocol Version 2 Control plane, is the LTE/EPS signaling protocol used by core network elements to create, modify, and tear down subscriber sessions. It carries control messages that update mobility, bearer, and forwarding state inside the mobile core.
It matters because control-plane messages are authoritative: if a network accepts forged, malformed, or out-of-context GTPv2-C traffic, an attacker may disrupt service, confuse session state, or influence how user traffic is routed. In real attacks and security testing, defenders look for weak validation of identifiers, session boundaries, and message order, since those mistakes can enable denial of service or state manipulation. Protecting GTPv2-C usually means strict segmentation, protocol-aware filtering, and careful state checking, not just syntax parsing.