Photo by Darius Bashar on Unsplash There are some important aspects to know about CVE-2019–1367 before diving into the technical analysis including the intel around it and the series of events following the in-the-wild exploitations and Microsoft patches. First of all, here is the bug class of this bug based on the Google P0 report: JScript variable (represented as VAR structure) isn’t properly tracked by garbage collector Is it important to understand the bug class.