There is a new bug in iOS that resprings most peoples phones due to a low memory crash. It is caused by iOS's inability to render certain strings of Arabic characters which overloads the memory, causing resprings and reboots or safe mode on a jailbroken device. Simply explained, when someone messages you those characters and you get a banner notification, your phone starts kicking the bucket.
A few developers have stepped in and saved the day for jailbreakers. This isn't the first or second time the jailbreak community receives a security fix quicker than Apple is able to push one to stock devices. It's a great example of the argument that jailbroken iOS, in the right hands, can be more secure than stock.