Anas (RAA) narrated that the Messenger of Allah (ﷺ) said:

“The atonement of backbiting a man is to ask Allah to forgive him.” Related by Al-Harith bin Abu Usamah with a weak chain of narrators.

وَعَنْ أَنَسٍ ‏- رضى الله عنه ‏- عَنْ اَلنَّبِيِّ ‏- صلى الله عليه وسلم ‏-قَالَ: { كَفَّارَةٌ مَنْ اِغْتَبْتَهُ أَنْ تَسْتَغْفِرَ لَهُ } رَوَاهُ اَلْحَارِثُ بْنُ أَبِي أُسَامَةَ بِسَنَدٍ ضَعِيفٍ.‏ [1]‏ .‏