Vulnerable Systems:
* Apple Safari version 5.0.2 and prior
* Apple Safari version 4.1.2 and prior
Immune Systems:
* Apple Safari version 5.0.3
* Apple Safari version 4.1.3
The vulnerability is caused by a use-after-free in WebKit when handling scrollbars, which could be exploited by remote attackers to execute arbitrary code by tricking a user into visiting a specially crafted web page.