Apple have released iOS 10.3.3 and it has a large number of fixes that you should apply as soon as you can.
iOS 10.3.3 fixes a number of security issues, that include:
- Arbitrary code execution with system and/or kernel privileges
- Disclosure of user information
- Unexpected application termination
- Address bar spoofing
- Multiple memory corruption issues
- Arbitrary code execution on the Wi-Fi chip
This last one for the Wi-Fi chip can allow attackers in Wi-Fi range to find and take over you device and crash it. This exploit is known as Broadpwn and has been given a 9.8/10 score US’s National Institute of Standards and Technology severity scale (NIST). It's not just an Apple problem, mobile devices with the Broadcom chip-set are likely to be at risk, Google has already patched it's devices.
More details can be found on the numerous fixes in 10.3.3 here https://support.apple.com/en-us/HT207923
How to update your iOS device click here https://support.apple.com/en-us/HT204204
Update and do the Cyber Essentials