During the last night the famous developer of tweaks to Cydia, Ryan Petrich, published through his profile Twitter, an image demonstrating Activator running on what appears to be iOS 7. The image has the dimensions of a screenshot taken on the terminal iPod Touch 5G, so we are not talking about a iPhone 4 which can be exploited using this method. Based on the alert displayed by Activator, which says that it cannot run on iOS 7 because it has not been tested, it is hard to say if we are talking about an image made using Xcode, or if root access was obtained on the terminal.
At the moment evad3rs and chpwn have exploits that allow the development of solutions jailbreak for iDevices, they were kept specifically for iOS 7, but it is unlikely that Ryan Petrich had access to one of them. Regardless of the situation, a jailbreak solution for iOS 7 it will be released anyway, so you shouldn't worry too much.
