There is an update for iOS 6... v6.1.6. But it is only available to iPhone 3GS and iPod touch 4th gen users. http://support.apple.com/kb/HT6146?viewlocale=en_US&locale=en_US
For iPad, the highest supported os for iOS 6 is v6.1.3. If you want to get the security patch, you'll have to go to iOS 7.0.6.
Hope this answers your question.