What is the ruling on circumambulating graves?

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.

Circumambulating graves is Shirk [associating partners to Allaah] because Circumambulation is an act of worship that is legislated by Allaah in a particular place, so whoever devotes this act of worship to other than Allaah in a manner which Allaah did not legislate, then he has indeed associated others to Allaah and legislated in religion that which Allaah did not legislate.

Allaah Knows best.