An elevation of privilege vulnerability exists when the Windows Shell fails to validate folder shortcuts. An attacker who successfully exploited the vulnerability could elevate privileges by escaping a sandbox. To exploit this vulnerability, an attacker would require unprivileged execution on the victim system. The security update addresses the vulnerability by correctly validating folder shortcuts.
https://www.tenable.com/blog/tenable-roundup-for-microsofts-june-2019-patch-tuesday
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1053
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2019-1053