It happened before, and it's happened again. Ahead of Battlefield 4's release for the Naval Strike DLC, it seems that the map names for the following two pieces of DLC - Dragon's Teeth and Final Stand - have already managed to slip out via Reddit.
According to Redditor LeakTheController, who claims the information was, "taken straight from EA's confluence page," Dragon's Teeth will arrive for Premium players on May 3. Everyone else will gain access two weeks later, May 17. The maps are: Propaganda, Waterfront, Urban Garden, and Marketplace.
As for Last Stand, that DLC will hit Premium players on September 2, and everyone else on September 16. The "proposed, not final yet" map names are Artic Research, Sub Base, Walker Factory, and Titan.
There's been no announcement from EA or DICE on the above information, so despite Controller's claim, we'll have to take this as a rumor for the time being. The only confirmed info we have on the remaining pieces of DLC is that Dragon's Teeth will feature a two-handed ballistic shield as a new item pick up.
The odds of this being legitimate are hard to say, but Controller has a decent track record. A week old comment from the Redditor describe an interesting Levolution event on Naval Strike's Lost Island map, claiming that the map's crashed plan centerpiece leaks fuel, and can be blown into pieces revealing a hidden rocket launcher. DICE confirmed that in a recent description of the maps a few days ago. That would make his claim of Final Stand adding in snowboards that much more tantalizing. Still, better to wait from EA or DICE before getting too excited.
Premium players are slated to get access to the game's Naval Strike DLC tomorrow, March 25, with general access set for April 8. More on that DLC here, along with a trailer.