In a large bowl, combine the cake mix, water, eggs and pumpkin. Beat on low speed just until moistened. Beat on medium for 2 minutes.
In a small bowl, combine brown sugar and cinnamon; cut in butter until crumbly. Fill paper-lined muffin cups one-fourth full with batter. Drop streusel by heaping teaspoonfuls into center of each cupcake. Cover with remaining batter.
Bake at 350° for 18-20 minutes or until a toothpick inserted in the cake portion comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
In a small bowl, beat cream cheese and butter until fluffy. Add confectioners’ sugar and vanilla; beat until smooth. Frost cupcakes. Store in the refrigerator.