It is narrated from Sayyidah Aishah bint Qudamah bin Maz'un (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) kissed Uthman bin Maz'un (may Allah be pleased with him) on his cheek after his death, and it is not known that he (peace and blessings be upon him) kissed anyone other than him in this way.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21225