iOS 8

Apple has released the latest version of its mobile OS on Wednesday, and in it has fixed over 50 vulnerabilities, many of which are very serious:
Two vulnerabilities allowed a local attacker to escalate privileges and install unverified (likely malicious) applications
A validation issue in the handling of update check responses allowed an attacker with a privileged network position to cause an iOS device to think that it is up to date even when it is not
Two vulnerabilities in CoreGraphics made it possible for a maliciously crafted PDF file to terminate apps or execute arbitrary code
Several vulnerabilities in the IOHIDFamily kernel extension made it posible for a malicious app to read kernel pointers, which can be used to bypass kernel address space layout randomization, or to execute arbitrary code with system privileges (the latter was also made possible by the existence of several IOKit bugs)
A Libnotify bug allowed a malicious application may be able to execute arbitrary code with root privileges
Two Safari vulnerabilities made it possible for attackers and websites to intercept or harvest user credentials
12 WebKit bugs could have been misused by attackers to execute arbitrary code on the device by simply creating a malicious website and tricking users into visiting it.
With iOS 8, Apple has also updated its certificate trust policy and has randomised the MAC address to prevent potential device tracking attacks via passive WiFi scans.

If you can, it’s a good idea to update to iOS 8, because all these bugs remain unpatched in all earlier version of the OS.

More information:
http://www.net-security.org/secworld.php?id=17378
http://support.apple.com/kb/HT6441