Sunan an-Nasa'i 1307
سنن النسائي#1307SahihIt was narrated that Farwah bin Nawfal said:"I said to 'Aishah: 'Tell me of a supplication that the Messenger of Allah (ﷺ) used to say in his prayer.' She said: 'Yes. The Messenger of Allah (ﷺ) used to say: Allahumma inni author bika min sharri ma 'amiltu wa min sharri ma lam a'mal (O Allah, I seek refuge with You from the evil of that which I have done, and the evil of that which I have not done)
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 Muslim
In-book reference: 13:129