I don't recall going through a security check when making a connection from the U.S. to Hungary through Frankfurt a couple years ago. I guess I'll get to test that again in May on my next connection there.
I can see having to go through security if you're connecting from a domestic flight to an international, or vice versa. But if you're connecting from one international flight to another, you never go outside the secure area, so why would you go through security again?