The Book of Pilgrimage
حَدَّثَنَا شَيْبَانُ بْنُ فَرُّوخَ، حَدَّثَنَا هَمَّامٌ، حَدَّثَنَا عَطَاءٌ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم دَخَلَ الْكَعْبَةَ وَفِيهَا سِتُّ سَوَارٍ فَقَامَ عِنْدَ سَارِيَةٍ فَدَعَا وَلَمْ يُصَلِّ .Ibn Abbas (Allah be pleased with them) reported that Allah's Apostle (ﷺ) entered the Ka'ba, and in it there were six pillars, and he stood near a pillar and made supplication, but did not observe the prayer
From Sahih Muslim, whose reports the scholars accept as authentic.