Ayesha reported,
The Messenger of Allah ﷺ said, "Any woman who marries without her guardian's consent, her marriage is invalid, her marriage is invalid, her marriage is invalid. If the man has consummated the marriage with her, she is entitled to her dowry for what he has taken from her. If they dispute, then the ruler is the guardian of whoever has no guardian."
Ibn Majah 1879
Sahihحدثنا أبو بكر بن أبي شيبة حدثنا معاذ بن معاذ حدثنا ابن جريج عن سليمان بن موسى عن الزهري عن عروة
عن عائشة قالت
قال رسول الله ﷺ أيما امرأة لم ينكحها الولي فنكاحها باطل فنكاحها باطل فنكاحها باطل فإن أصابها فلها مهرها بما أصاب منها فإن اشتجروا فالسلطان ولي من لا ولي له
[Sahih] Recorded by Abu Dawud in the Book of Marriage, chapter on the guardian, hadith no. 2083, from the hadith of Ibn Jurayj through this route. Ibn Hibban and Hakim graded it sahih. It has many corroborating narrations, and the hadith "There is no marriage without a guardian" is mutawatir, as Suyuti stated in Qatf al-Azhar, hadith no. (87), and others also stated. It is likewise mutawatir from the companions 
in their legal rulings. See Sunan al-Kubra by Baihaqi, 7/111, and others.