[Ruling on Selling the Pledged Item]

Answer—and Allah is the One who grants success: The jurists of the madhhab did not permit the pledgee to sell the pledge unless the pledger authorizes him to sell it or empowers him to do so.
The solution is that, if the pledgee has not been authorized to sell the pledge, he should go to the judge and request a ruling to sell the pledge. The judge then deputes someone on his behalf to sell it. When the judge sells it, the pledgee takes the price, satisfies his due from the debt, and the remainder is preserved for its owner.
In sum: the pledgee may sell the pledge in two cases:
First: the pledger authorizes him or empowers him to sell it.
Second: the judge orders him to sell it.
He is not permitted to sell it in other than these two cases. The proof for what we have mentioned is His saying: “Do not consume one another’s wealth unjustly—unless it be a trade by mutual consent among you.” [al-Nisāʾ:29] and [the report] of the Prophet (May Allah bless him and his family and grant them peace), “The property of a Muslim is not lawful (to take) except with the cheerful consent of his soul.”
Thus, if there is no consent from the pledger for the sale, nor anything indicating the cheerful consent of his soul to it, the pledgee may not sell.
We only said that the judge may sell the pledge—or appoint one to sell it—even without the pledger’s permission, due to His saying: “And when you judge between people, judge with justice.” [al-Nisāʾ:58] and “O David, We have made you a successor on earth, so judge between people in truth.” [Ṣād:26]
There is no doubt that among justice and truth is that some people be given redress against others, and that every rightful claimant receive his due, whether they like it or not. This is the very benefit and intended purpose of appointing judges.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2