The GP included "accidentally backdoored", in which case that's probably all of them. Even if you exclude accidents, there are probably some deliberately create

The GP included "accidentally backdoored", in which case that's probably all of them. Even if you exclude accidents, there are probably some deliberately created, not-yet-burned covert access techniques for many devices. We don't know what we don't know, but we do know there are agencies tasked with Total Information Awareness, and have some evidence of the type of stuff they get up to.