The rumors have swirled for a while now. Various people who have worked on the show have dropped hints. But now David Benioff and D.B. Weiss, Game of Thrones’ showrunners, have officially, irrevocably confirmed that we only have 15 episodes of the show left… at most. Probably less.
Source: io9 – Game of Thrones Showrunners Confirm There Are Only 15 Episodes Left, Max