Per: http://support.apple.com/kb/HT5052 'This issue does not affect devices running iOS prior to version 4.3.'
Apple iOS is prone to a security-bypass vulnerability that affects the code signing security feature.Attackers can exploit this issue by enticing an unsuspecting user to install a specially crafted application on the affected device.Successful exploits will allow attackers to bypass certain security restrictions and execute arbitrary code on the affected device.Apple iOS 4.3 through 5.0 are vulnerable.
Updates are available. Please see the references for more information.
An attacker must trick a victim into installing a malicious application to exploit this issue.A video demonstrating the issue is available. This exploit is not otherwise known to be public or circulating in the wild.