Authentic
graded by Al-Albani
Mishkat al-Masabih 4264
Narrator:Ibn ‘Abbās
وَعَنِ ابْنِ عَبَّاسٍ قَالَ نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَن الشّرْب من قي السقاء
Ibn ‘Abbas said God’s messenger forbade drinking from the mouth of a water-skin. (Bukhari and Muslim.)
Cited in Mishkat al-Masabih (No. 4264).