Disney says
1/3 lb Angus Beef Patty, Cheddar Cheese, 1000 Island, and Caramelized Onions on an  Allergy-friendly Bun with Cuties® Mandarin Oranges or Steak Fries.
Friendliest.app says
The Ka-Cheeseburger can be served on an allergy-friendly bun that is free of gluten/wheat, milk, fish, shellfish, peanuts, tree nuts and soy.

Steak fries are cooked in a dedicated fryer to reduce cross-contamination.

This meal contains milky (cheese), eggs (bun/dressing) and soy (steak fries). It can be made milk-friendly by omitting the cheese. It can be made soy-friendly by selecting mandarin oranges instead of steak fries. 

If ordered with a sesame seed bun and without dressing this meal is egg-friendly, but introduces other allergens.