What is the ruling on a father concealing the true lineage of his children and attributing them to a family other than their own, while the family is aware of this and denies their lineage for fear of severing kinship ties, and do they fall under the ruling of being cursed?

A father concealing the true lineage of his children and attributing them to a lineage other than their real one is a great sin and an enormous transgression. This is due to the severe warnings mentioned in the prophetic hadiths for anyone who claims a lineage other than that of his father, or disowns him, or affiliates himself with other than his masters. These warnings include expulsion from Paradise, curses, and the non-acceptance of any obligatory or voluntary act. This warning encompasses the father and anyone who assists him, as well as the children if they know their true lineage and attribute themselves to another. It is obligatory upon them to seek forgiveness and to rid themselves of this false attribution.