Is it permissible to break a fasting vow for an oath due to hunger?

It is permissible to break the fast of an expiation for an oath (kaffarat al-yameen) and to break one's fast in cases of unusual severe hunger or thirst. That day must then be made up, based on the Almighty's saying: "And He has not placed upon you in religion any difficulty." Furthermore, continuous fasting for the three days is not obligatory according to many scholars.