Preheat oven to 400°F.
Cut brie into 24 small pieces.
Arrange phyllo shells on a rimmed baking sheet; place 1 brie piece in each phyllo shell.
Top each shell with 1 teaspoon cranberry sauce; sprinkle evenly with pistachios.
Bake in preheated oven until cheese is melted and bubbly, about 6 minutes.
Serve immediately.
