The Messenger of Allah ﷺ said, "A Muslim is the brother of another Muslim. It is not lawful for a Muslim to conceal from his brother a defect in his merchandise that, if known, would cause him to refrain from buying it."
حدثنا يحيى بن إسحاق حدثنا ابن لهيعة عن يزيد بن أبي حبيب عن ابن شماسة
قال رسول الله ﷺ المسلم أخو المسلم لا يحل لامرئ مسلم أن يغيب ما بسلعته عن أخيه إن علم بها تركها
No references are available.
Its isnad is hasan. Ibn Majah reported it, 2/755, no. 2246, in the Book of Trade, in the chapter, "Whoever Sells Something Should Disclose Its Faults."