Preheat the oven to 325 degrees F (165 degrees C). Grease two 9×5-inch loaf pan with cooking spray.
Combine flour, sugar, pumpkin pie spice, and baking soda in a large bowl.
Combine pumpkin puree, eggs, milk, and oil in a separate bowl. Add to the dry ingredients and beat until well combined. Add cranberries and stir to blend. Divide batter between the prepared pans.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour. Cool in the pans for 10 minutes, then remove to cooling racks to cool completely.