What is the religious ruling regarding a wife who allows a non-mahram man to stay overnight in her house in her husband's absence?

If a woman allows a strange man into her husband's house without his permission, she is sinful and disobedient (nashiz), and she must repent. If she does not, the husband has the right to discipline her. Her sisters must also repent if they participated in this act. The presence of more than one woman with a man does not negate seclusion (khalwa) according to some scholars, especially if there is a fear of temptation (fitna).