Combating Military Sexual Assault Act This bill addresses the prevention, investigation, and prosecution of sexual assault and related offenses in the Armed Forces. For example, the bill (1) expands training for, and responsibilities of, commanders of the Armed Forces with respect to such assaults; (2) extends the Defense Advisory Committee on Investigation, Prosecution, and Defense of Sexual Assault in the Armed Forces; (3) increases the number of digital forensic examiners in each military criminal investigation organization; (4) expands the authority of military judges with respect to certain pretrial matters; (5) makes sexual harassment a specific offense in the Uniform Code of Military Justice; and (6) and requires a pilot program on defense investigators within the military justice system.