A remote code execution vulnerability exists when the Microsoft Speech API (SAPI) improperly handles text-to-speech (TTS) input, aka 'Microsoft Speech API Remote Code Execution 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-2019-0985