Preheat oven to 350 degrees. Paper-line or grease 24 muffin cups. Blend cake mix, pumpkin, eggs, vegetable oil and water in large mixer bowl until moistened. Beat medium speed for 2 minutes. Pour batter into prepared muffin cups, filling 3/4 full. Bake for 18 to 23 minutes or until wooden pick inserted in center comes out clean. Cool in pans on wire racks for 10 minutes; remove to wire racks to cool completely. Spread cupcakes with frosting.