A person asked Sayyiduna Ibn Abbas (may Allah be pleased with them both) about the ruling of kissing while fasting, so he replied that once the Prophet (peace and blessings be upon him) kissed the head of one of his wives and at that time he (peace and blessings be upon him) was fasting.
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 3391
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد ضعيف لجهالة الشيخ من بني سدوس