What is the truth about the KGB's involvement in the "Hitler's diaries"?

As it is known, Hitler's Diaries (the fake diary of Adolf Hitler) were forged by Konrad Kujau, and sold to the Nazis' favourite "history" magazine (Stern) as authentic diaries, whose authenticity was confirmed by the greatest "Hitler expert" of Germany, namely Werner Maser. It later became clear that the diaries were fake. However, it was claimed that the KGB was involved in this scandal. So what is the truth?