Sunan an-Nasa'i, Hadith 5044 ⓘ
It was narrated that Abu Hurairah said: "Five things are of the Fitrah: Clipping the nails, trimming the mustache, plucking the armpit hairs, shaving the pubes, and circumcision." (Sahih Mawquf)
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنِ الْمَقْبُرِيِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ خَمْسٌ مِنَ الْفِطْرَةِ تَقْلِيمُ الأَظْفَارِ وَقَصُّ الشَّارِبِ وَنَتْفُ الإِبْطِ وَحَلْقُ الْعَانَةِ وَالْخِتَانُ .
also referenced under: Book 48, Hadith 5 (In-Book) & Volume 6, Book 48, Hadith 5047 (DarusSalam)