Apple has just released iOS 9.3.5, it may seem like a very small and unnecessary update because it's only about 41 MB, but looks can be misleading.
It solves very dangerous exploitation found in older versions of iOS 9.3 like 9.3.4 or 9.3.3, which allowed hackers to have full control over iPhone by installing malicious software. If they do, they will have access to all of your files, they can enable the camera on your device without noticing. It is spread of links sent in iMessage or Texts from Unknowns senders.
If you are jailbroken on iOS 9.3.3, you can save only, do not open link form Unknown, clicking on it can not stop it.