Merely ten days after making iOS 4.3.4 available for download, Apple has yet again released another update to iOS 4. They have now released iOS 4.3.5 and it is available for download through the links given in this post, or directly via iTunes.
The iOS 4.3.5 changelog doesn't come bearing any juicy details. It only provides the following reason for which iOS 4.3.5 is now available for download.
A security issue has been resolved with certificate verification.
Previously, it was thought that after iOS 4.3.3, Apple will straight away release iOS 5. However, with the discovery of a security exploit in mobile Safari, the exact same exploit used by Comex for jailbreaking iPad 2 as well as other iOS devices, Apple had to release a software update to patch that vulnerability. Regardless of the fact that Comex himself released PDF Patcher 2 in Cydia to patch this vulnerability while allowing you to retain your jailbreak. Apple released iOS 4.3.4 and fixed this vulnerability in mobile Safari, but it obviously didn't let you retain your jailbreak.
This time, it looks like Apple has had a head start against the hackers. It is possible that the company had located a potential exploit that could be used by hackers to develop another jailbreak, both tethered or untethered. So before it could have been exploit, it looks like Apple has released iOS 4.3.5 as a pre-emptive measure against any future jailbreak, at least on iOS 4.3.x.
Regardless of that, we do know that devices susceptible to the Limera1n bootrom exploit can and will always be able to be jailbroken. So yes, iOS 4.3.5 can also be jailbroken but for now it is going to be a tethered jailbreak. There's really no point for the devs to release an untethered jailbreak right now, as soon iOS 5 will be released and even though you can jailbreak iOS 5 tethered, people will definitely be seeking for an untethered jailbreak.
You can direct download iOS 4.3.5 ipsw for iPhone, iPad and iPod touch using the official Apple links given below.