All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The passing of wind whether it is during ablution or after finishing ablution invalidates it [ablution]. So, whoever passes wind while performing ablution is obliged to start it again from the beginning as the part of ablution which he performed beforehand is invalidated.
Allaah Knows best.