DEFCON 32 is not – repeat, not cancelled.
It sounds like it was a near thing, though.
According to a post on the forums by Dark Tangent, “Caesars abruptly terminated their contract with DEF CON” seven months before the convention, leaving DEFCON with no location.
The current plan seems to be to hold DEFCON at the Las Vegas Convention Center, “with workshops and training at the Sahara Hotel”. If you’re planning to go, it sounds like your best bet on a place to stay is probably a hotel on the monorail route.
There’s a pretty lively discussion, with a lot of speculation, in the Hacker News thread (where I first heard about this).