What is the ruling on seeking intercession through shrines?

Entreating through shrines has two meanings. The first is supplicating their occupants and seeking their aid, which is major polytheism (shirk (definition) akbar) that expels one from Islam. The second is supplicating Allah through the status of their occupants, which is an innovative form of entreaty (tahwassul bid'i) that was not reported from the Prophet, peace and blessings be upon him, nor from the Companions. As for the legitimate entreaty (tahwassul mashrou'), it is entreating through the Beautiful Names and Attributes of Allah, or through one's righteous deeds, or through the supplication of a righteous living person.