A denial of service vulnerability exists when Windows improperly handles objects in memory. An attacker who successfully exploited the vulnerability could cause a target system to stop responding. To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted application. The vulnerability would not allow an attacker to execute code or to elevate user rights directly, but it could be used to cause a target system to stop responding. The update addresses the vulnerability by correcting how Windows handles objects in memory.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0716