Is it obligatory to rinse the mouth when performing ablution during fasting, despite fearing the water might enter the pharynx?

A fasting person should not abandon rinsing the mouth (madmadah) during ablution (wudu') out of fear that water might reach the throat, because it is a Sunnah. Many scholars have even gone so far as to say it is obligatory. The Prophet, peace and blessings be upon him, forbade excessive snorting of water (mubalagah fi al-istinshaq), not the act of rinsing the mouth itself. If water reaches the throat unintentionally, it does not invalidate the fast.