What is the legal ruling on cursing Abraham (peace be upon him), and what is the responsibility of a website administrator who allows a phrase that includes cursing Abraham?

Scholars have agreed upon the disbelief (kufr) of anyone who reviles a prophet, or demeans or disparages him. Ishaq ibn Rahawayh mentioned the consensus of Muslims on the disbelief of anyone who reviles Allah or one of His messengers, or rejects anything Allah has revealed, or kills a prophet.

It is stated in "Manh al-Jalil" that the ruling on one who reviles prophets or angels, or shows contempt for them, or denies them, is the same as the ruling on one who reviles the Prophet Muhammad, may Allah bless him and grant him peace.

Accordingly, whoever utters such a statement has committed disbelief and exited the religion of Muslims. Scholars have mentioned that the one who reviles the Prophet is to be killed without being asked to repent, and this is incumbent upon the Muslim ruler, not individual people. It is obligatory to denounce and prevent this evil, and remaining silent about it, when one is able to denounce it, is a great evil.