It does. Click the "i" button: Map data © OpenStreetMap contributors, CC-BY-SA
There is some OSM community discussion on the UX behind this here: http://www.openstreetmap.org/user/lxbarth/diary/21769
For the OSM data Apple do use, I think it's quite old OSM data from 2010-2011 or something. As far as I remember, they used that because the license changed after that, so I believe that's under different terms.