Place cake mix in the bowl of a stand mixer. Add buttermilk, vegetable oil, and eggs; beat 2 minutes on medium speed.
Fill bake-in-cups just over half full with batter using an ice cream scoop. Bake 350° for 14-16 minutes, or until a toothpick inserted comes out clean. Allow to cool before frosting.
Cut a hole at the bottom of one of the frosting bags and insert frosting tip. Add yellow frosting to the bag and pipe a circle around the outer edge of each cupcake. Repeat with orange and white frostings using a different frosting bag for each and create a candy corn look. Serve and enjoy!