Ikrimah (may Allah have mercy on him) narrates from Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "Any man who has an umm walad, she is free after his death."
Husayn bin Abdullah bin Ubaydullah bin al-Abbas al-Hashimi (one of its narrators) was declared weak by most of the scholars of hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21781