Musnad Ahmad 27:682

Muhammad ibn Ja'far and Hajjaj narrated to us, they said: Shu'bah narrated to us, from 'Abdullah ibn Dinar, [who said]: I heard Ibn 'Umar narrating "that the Prophet (ﷺ) forbade *wars* (a yellow dye) and saffron." Shu'bah said: I said to him, "Meaning for the *muhrim* (one in the state of ihram)?" He said, "Yes."