updated 05:04 pm EDT, Thu September 19, 2013
Mimics previously-documented vulnerabilities
[Update: Apple acknowledges issue, says fix is on the way] A newly-documented technique lets people bypass an iOS 7 device's security to look at personal photos, according to accounts. Several steps are involved: swiping up Control Center from the lockscreen, opening Stopwatch, opening the Alarm Clock, holding down the power button until the "Power Down" prompt appears, then finally tapping Cancel and double-tapping the home button twice, but slightly longer on the second press. This opens up the multitasking menu, from which point a person can jump into the Camera app and browse or share a person's photos.
The bypass works on both iPhones and iPads. It should, however, be relatively easy to defeat. It only works if Camera is a recently-opened app on a device, and lockscreen access to Control Center can be disabled via iOS' Settings app.
The hack is similar to several that have been used against previous versions of iOS. It's not clear why the issue keeps reappearing, despite repeated fixes by Apple.
Update: Apple has acknowledged the problem and says it will fix the issue in a "future software update." No timetable was given in the company's brief statement, but the spokesperson said that "Apple takes user security very seriously." In the meantime, simply disabling lockscreen access for Control Center will prevent any issue with the flaw.