Hostile Mobs in Boats and Carts Have Extended Hit Range

Hostile mobs that usually have a melee hit range of <1 block, are able to hit you from up to 4 blocks away when they are riding in a boat.

To reproduce, approach a hostile mob* that is riding a boat. Notice that it can attack you from up to 4 blocks away.

*Includes
Silverfish
Angered Wolf
Zombie
Pigman

Their range is also increased slightly when they are riding a minecart also.