Microsoft releases 50 security fixes for problems in ChakraCore, Hyper-V Server, Windows, Microsoft Office, and Office Services. Of these, 11 are rated as Critical severity and 39 are ranked Important. None of the bugs were under active attack at the time fixes were released, though one was publicly known. Microsoft also released updates for Speculative Store Bypass, otherwise known as Spectre Variant 4, discovered in May. An interesting, though not critical, vulnerability in Windows 10 lets attackers bypass the lock screen through a default configuration for Cortana.”]
Source: https://www.darkreading.com/cloud/microsoft-fixes-11-critical-39-important-vulns