The Messenger of Allah ﷺ said, "Any slave who marries without the permission of his masters is a fornicator."
حدثنا أحمد بن حنبل وعثمان بن أبي شيبة وهذا لفظ إسناده وكلاهما عن وكيع حدثنا الحسن بن صالح عن عبد الله بن محمد بن عقيل
قال رسول الله ﷺ أيما عبد تزوج بغير إذن مواليه فهو عاهر
Its isnad is daif. Tirmidhi transmitted it in "Nikah," the chapter on what has been said about a slave's marriage without his master's permission, hadith no. 111, from the hadith of Ibn Aqeel with this wording, and he said, hasan. It is also found in Musnad Ahmad, 3/301, and Hakim graded it sahih, 2/194, and Dhahabi agreed with him.Ibn Aqeel is daif, as noted previously, hadith no. 126. This hadith has a daif corroborating narration in Ibn Majah (1960). Bayhaqi (7/127) and Ibn Abu Shayba (4/261, hadith no. 16858), the wording being his, narrated with a strong chain from Ibn Umar, who said, "A slave's marriage without his master's permission is fornication, and the one who married him off is to be punished."