Sayyiduna Anas (may Allah be pleased with him) narrates: the Prophet (peace and blessings be upon him) forbade fasting on six days of the year: the day of Eid al-Fitr, the day of Eid al-Adha, and the three Days of Tashriq.
Imam Abu Ya'la recorded it, and it is da'if (weak) through all of its routes.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5238