Shortly after releasing iOS 4.3.4, Apple has released iOS 4.3.5. The update is for iPhone 3GS/4G users aswell as for the iPod Touch 3G/4G and the iPad 1G/2G. The update fixes a security issue with certificate validations:
A certificate chain validation issue existed in the handling of X.509 certificates. An attacker with a privileged network position may capture or modify data in sessions protected by SSL/TLS. Other attacks involving X.509 certificate validation may also be possible. This issue is addressed through improved validation of X.509 certificate chains.
For more details check out this page.
