Preheat the oven to 350F and line a muffin tin with paper liners.

Stir the cake mix, pumpkin puree, and water together until just combined.

Divide the batter evenly among the muffin cups.

Bake for 18 to 20 minutes, until a toothpick comes out clean.

Cool in the pan for 5 minutes, then move to a rack.