The Messenger of Allah ﷺ said, "Any woman who marries without the permission of her guardians, her marriage is invalid," repeating it three times. "If he has consummated the marriage with her, then the dowry is hers in return for what he has taken from her. If they dispute, then the ruler is the guardian of one who has no guardian."
حدثنا محمد بن كثير أخبرنا سفيان أخبرنا ابن جريج عن سليمان بن موسى عن الزهري عن عروة
قال رسول الله ﷺ أيما امرأة نكحت بغير إذن مواليها فنكاحها باطل ثلاث مرات فإن دخل بها فالمهر لها بما أصاب منها فإن تشاجروا فالسلطان ولي من لا ولي له
[Sahih] Reported by Tirmidhi, in the Book of Marriage, chapter "There is no marriage without a guardian," hadith no. 1102, from the hadith of Sufyan through this chain. He said, "Hasan." Ibn Majah also reported it, hadith no. 1879, and Ibn Hibban graded it sahih, hadith no. 1248, as did Hakim, according to the criteria of the two Shaykhs, 2/168. Ibn Jurayj heard it from Sulayman bin Musa, and Zuhri heard it from Urwa. It has been criticized, but with something that does not invalidate it.