Preheat the oven to 325 degrees F (165 degrees C). Coat two 9x5-inch loaf pans with cooking spray.

Combine flour, sugar, pumpkin pie spice, and baking soda in a large bowl.

Combine pumpkin purée, eggs, milk, and oil in a separate bowl; beat into flour mixture until well combined. Fold in cranberries. Divide batter between the prepared pans.

Bake in the preheated oven until a toothpick inserted into centers comes out clean, about 1 hour. Cool in the pans for 10 minutes, then transfer to wire racks to cool completely.