In a narration of al-Mu'jam al-Awsat the words are: The Prophet (peace and blessings be upon him) saw no harm in making up (missed fasts of) Ramadan in the (first) ten days of Dhu al-Hijjah. The chain of the first narration, and of this one too, contains Ibrahim bin Ishaq al-Sini, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5068