What is the ruling on one who swore a false oath on the Qur’an while angry and unaware of what he was doing, concerning changing the password of an electronic account that does not result in financial or personal harm?

Swearing falsely about a past event is an al-Yamin al-Ghamus (a perjurious oath), and it is among the major sins for which, according to the majority of scholars, no expiation for an oath (kaffarat yamin) is sufficient. Hacking someone's account and changing their password is a sin and an aggression strictly forbidden by Islamic law. Anger and nervousness do not prevent the oath from taking effect as long as one's sanity remains intact. Repentance to Allah for these sins is obligatory.