Sunan an Nasai
1330
Hasan Sahih+2

It was narrated from Abu Hurairah that:"The Messenger of Allah (ﷺ) said the salam then he performed two prostrations of forgetfulness while he was still sitting, then he said the salam." He said: He mentioned it in the hadith of Dhul-Yadain

Hasan SahihAbu Ghuddah
Hasan SahihAl-Albani