Sunan Abi Dawud 1016
سنن أبي داود#1016SahihAbu Hurairah reported; He then made two prostration on account of forgetfulness after he had given the salutation
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan Sahih
Muhammad Muhyi Al-Din Abdul HamidHasan Sahih
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Hasan
In-book reference: 2:627