The evad3rs, a group of hackers who released the jailbreak for iOS 6, have announced that they are now actively investigating iOS 7 to identify which of their exploits still work.
Planetbeing tweeted the news moments ago:
Since everyone loves updates: @evad3rs have now started to actively look at iOS 7.
We are currently in a reconnaissance phase where we are identifying which exploits we have still work.
Since the Gold Master of iOS 7 has been released to developers it is too late for Apple to make any changes to the software before the iPhone 5s and iPhone 5c hit shelves.