Siri flaw allows anyone to disable cellular data on your iPhone without a Passcode
If you ask Siri to disable Cellular Data on an iPhone running iOS 9 through the iOS 10.3.3 beta, she will tell you that this cannot be done without entering the Passcode of the particular device. Nothing wrong there, because that is exactly what you want to happen with your iPhone. But instead, if you ask Siri about the Cellular Data setting and the status of it, a bug takes over and shows a toggle switch that will allow you (or anyone hip to this flaw) to turn off Cellular Data if it is already on, and vice versa. And this is all possible because the Passcode protection is bypassed by the flaw.
As we said earlier, this is more of a nuisance than anything because this flaw is not revealing any personal information. If you're a joker who likes to leave every iPhone user they meet without cellular data, congratulations. You bewildered a few people. The joke, however, is on you. After all, disabling an iPhone from cellular support is as easy as turning on the Airplane Mode on the phone.
source: Reddit via RedmondPie