BlueKeep is the nickname for CVE-2019-0708, a remote code execution vulnerability in older versions of Windows Remote Desktop Services. A remote attacker can exploit it through RDP without valid credentials if the target system is unpatched and exposed.
It matters because RDP is often reachable from the internet or a large internal network, so a single vulnerable host can become an entry point into a Windows environment. In real attacks, BlueKeep can provide the first foothold for further intrusion, lateral movement, or follow-on identity abuse against systems such as domain controllers. Defenders reduce the risk by patching legacy Windows systems, limiting RDP exposure, using network segmentation, and monitoring for unusual remote access to vulnerable hosts.