This security update corrects a denial of service in the Local Security Authority Subsystem Service (LSASS) caused when an authenticated attacker sends a specially crafted authentication request, aka 'Local Security Authority Subsystem Service Denial of Service Vulnerability'.
https://www.tenable.com/blog/tenable-roundup-for-microsofts-june-2019-patch-tuesday
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0972