Yes — al-gharimun, those burdened by debt, are explicitly one of the eight categories in Quran 9:60. This covers a person who took on debt for a lawful need and genuinely cannot repay it, and also the one who shouldered a financial burden (hamalah) to reconcile between disputing parties; the Prophet ﷺ told Qabisah ibn Mukhariq, who had borne such a burden, to wait until the zakat came so it could be given to him. Many scholars permit paying the creditor directly on the debtor's behalf with his knowledge and consent, while others require handing it to the debtor himself so that he takes ownership of it. Someone whose debt arose from sin or extravagance is not helped from zakat until he repents, and there is genuine ikhtilaf over settling the debts of a deceased person from zakat — the majority do not allow it since zakat requires transfer of ownership to a living recipient, so this should be avoided.
Q&A · Zakat
Can zakat be used to pay off someone's debt?
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.