Can bosses talk to one employee about another employee's personal life? Or another employee in general?

My boss spoke with one of my coworkers about me and my personal life, probing questions from them. They felt uncomfortable and told me to go talk to my boss. Is that legal for a boss to question another employee about me and my personal life or performance at the job? If not what are my rights and what can I do. I feel violated and uncomfortable going back to work!