An iPhone that has an access code set, a security code, should be so secure that no one should be able to access it to retrieve its data. The Apple company fought in court with the FBI to prove that it does not have access to the existing data in an iPhone that has set an access code, but every month we are shown that the Americans are lying.
In the video clip below you can see a demonstration of a method by which data can be accessed from an iPhone that has an access code set. We are talking about the photo/video library, the contact book or the logs of our messages, controlling certain settings is also possible even if the terminal is, theoretically, blocked.
Practically, any person with bad intentions could access these data in just a few seconds and without struggling too much, something that Apple constantly tries to avoid. The method works with any kind of iPhone terminal, as long as it has Siri active, so if you use Voice Control, or don't use any of these systems, you might be safe.
Considering the very serious way in which the Apple company continues to secure its iOS operating system, it is very possible that this bug will be closed very soon. At the moment it works in iOS 8 – iOS 10.2 beta 3, but probably in the next updates it will be blocked by those from Cupertino.
