A remote code execution vulnerability exists when the Windows Jet Database Engine improperly handles objects in memory. An attacker who successfully exploited this vulnerability could execute arbitrary code on a victim system. An attacker could exploit this vulnerability by enticing a victim to open a specially crafted file. The update addresses the vulnerability by correcting the way the Windows Jet Database Engine handles objects in memory.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1155