The Messenger of Allah ﷺ said: The marriage of a woman who marries without the consent of her guardians is void. (He said these words) three times. If there is cohabitation, she gets her dower for the intercourse her husband has had. If there is a dispute, the sultan (man in authority) is the guardian of one who has none.
قَالَ رَسُولُ اللَّهِ ﷺ أَيُّمَا امْرَأَةٍ نَكَحَتْ بِغَيْرِ إِذْنِ مَوَالِيهَا فَنِكَاحُهَا بَاطِلٌ ثَلاَثَ مَرَّاتٍ فَإِنْ دَخَلَ بِهَا فَالْمَهْرُ لَهَا بِمَا أَصَابَ مِنْهَا فَإِنْ تَشَاجَرُوا فَالسُّلْطَانُ وَلِيُّ مَنْ لاَ وَلِيَّ لَهُ