VRF stands for Virtual Routing and Forwarding. It lets one physical network device maintain multiple separate routing tables, so traffic in one VRF is logically isolated from traffic in another. Think of it as running several independent networks on the same switch or router without them sharing routes by default.
In cyber security, VRFs matter because segmentation reduces blast radius. If a service, management interface, or exposed port lives in the wrong VRF, it may become reachable from places defenders did not intend. Attackers often look for exactly that kind of exposure: a service that is assumed to be private but is reachable in the default VRF or another routed context. Defenders use VRFs to separate management, user, guest, and infrastructure traffic, then restrict route leaking and firewall rules between them. In practice, checking which VRF an interface or port belongs to is a core step in validating whether a vulnerability is actually exposed.