Keeping the Fast free from Imperfection - Section 1 Mishkat al-Masabih 2002
Arabic hadith text
وَعَنِ ابْنِ عَبَّاسٍ قَالَ: إِنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ احْتَجَمَ وَهُوَ مُحْرِمٌ وَاحْتَجَمَ وَهُوَ صَائِمٌ
Translation
Ibn ‘Abbas said that the Prophet had himself cupped when he was wearing the ihram and also when he was fasting. (Bukhari and Muslim.)