This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Apple Safari's Webkit. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the library's support for mouse events on a particular element. If a mouse event is dispatched to an element when one of it's attributes is undefined, the library will dereference a memory pointer pointing to arbitrary data. Usage of this element can then lead to code execution under the context of the application.