It is narrated from Qasim bin Muhammad, he said: I was with Ibn Abbas (may Allah be pleased with them) when he mentioned the case of those who perform li'an (mutual cursing). So Abdullah bin Shaddad said to him: "Was this the same woman about whom the Prophet (ﷺ) said: 'If I were to stone someone without evidence, I would have stoned this woman'?" Ibn Abbas (may Allah be pleased with them) replied: "No, she used to commit indecent acts openly."
Hadith Referenceمسند الإمام الشافعي / كتاب اللعان / 1334
Hadith Takhrijاخرجه البخاري، الحدود، باب من اظهر الفاحشة واللطخ والتهمة بغير بينة (6855)، (7238) ومسلم، لعان (1497)۔