A 15-year-old Bennett High School student has been arrested on third-degree assault and harassment charges for injuring a school security officer who was trying to break up a fight between the suspect and another student during a noontime cafeteria incident at the Main Street school Monday, Buffalo police reported Wednesday. The student, who was suspended from school, lives on Norfolk Avenue, police said. A security officer suffered a deep cut to his right hand in subduing the suspect, according to a police report.