Kellogg's All Bran is definitely NOT gluten-free as it contains wheat or other gluten-containing ingredients.

Does bran have gluten?

Wheat bran contains gluten. A kernel of wheat grain contains three parts: the germ, endosperm and bran. ... The bran, or tough outer coating of the kernel, is also removed during the manufacturing process for white flour. All three components contain a plant storage protein known as gluten.

What cereal is free from gluten?

Chex Cereal

Rice, corn, honey-nut, cinnamon, chocolate, vanilla, blueberry... all these flavors are banded as gluten-free cereals.