Apple has released software update fixing a vulnerability in iOS versions prior to iOS 9.3.4. This vulnerability is caused by a memory corruption security flaw.
> iPhone 4s and later
> iPad 2 and later
> iPod touch (5th generation) and later
A successful attack could lead to execute arbitrary code with kernel privileges.
The product vendor has released iOS 9.3.4 to address the issues. Users can obtain the updates by using the auto-update mechanism. Users of affected systems should follow the recommendations provided by the product vendor and take immediate actions to mitigate the risk.
https://support.apple.com/kb/HT207026
https://www.hkcert.org/my_url/en/alert/16080801
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=2016-4654