Hello aspirant, 

 There is  open education system in USA, you are free to apply for any specialization or major as you wish. You would need to articulate in your Statement of Purpose, when you apply for MS, why you decided to pursue a different major. Since your admission decision is not based on your Major or specialization in Bachelors. It will depend on your academic excellence and standardized test scores like GRE and TOEFL.

The school will include in your admission letter stating all the pre-requisite courses that you need to do for the MS program.  The prerequisites are mandatory as you are switching majors or getting acquainted with a new specialization.  So, all your basics and foundations of any major or specialization are covered with pre-requisites and you can pursue your dream education .

All the best!!