Sunan an-Nasa'i 1782
سنن النسائي#1782SahihIt was narrated that Ibn 'Abbas said:"The Prophet (ﷺ) used to pray two rak'ahs of Fajr when he heard the Adhan and he made them brief
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 20:185