A popular iOS hacker Stefan Esser, who is better known by his Twitter handle, @i0n1c, have claimed that he can crack iOS 8 after sometime and he certainly has come through on that claim.
On his twitter account he has posted a image, which shows the ability to SSH into an iPod touch running iOS 8 beta 1 through Mac. Its not possible to SSH into an iOS device until and unless its jailbroken, so this is proof enough.
Mostly Jailbreaker community didn't publish the Jailbreaks for beta firmwares as its basically inviting Apple to patch the exploit in the subsequent beta release.
So if the above claimed gets work then Apple have get more serious on it iOS 8 security before its public announcement.
After seeing the above claim, I just got remember a sentence which I really like, Security is Just an Illusion.