Immune Systems:
* Apple Safari 4.0.5
* Apple iPhone iOS 4
* Apple iPod touch iOS 3.2
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 due to the method by which the Webkit library renders right-to-left text. If a linebox has a width greater than it's container, Webkit frees an object that upon page destruction is freed again. An attacker can exploit this to code execute remote code under the context of the application.
Patch Availability:
This issue was fixed in Safari 4.0.5, and iOS 4 for iPhone and iPod touch iOS 3.2:
iOS 4: http://support.apple.com/kb/HT4225
Safari 4.0.5: http://support.apple.com/kb/HT4070