Sahih Muslim 899
صحيح مسلم#899SahihThis hadith has been narrated on the authority of Mansur with the same chain of transmitters and he made a mention of this:" Then he may choose any supplication which pleases him or which he likes
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 4:61