The Messenger of Allah ﷺ said, "Every sin of the martyr is forgiven except debt."
حدثنا يحيى بن غيلان حدثني المفضل حدثني عياش بن عباس عن عبد الله بن يزيد أبي عبد الرحمن الحبلي
أن رسول الله ﷺ قال يغفر للشهيد كل ذنب إلا الدين
Its isnad is sahih. Mufaddal is Ibn Fadala the Egyptian, whose reliability was established earlier at 821, and it should be added here that Bukhari recorded him in Kabir 4/1/405. Ayyash is spelled with a ya and ends with a shin, and his father is Abbas, spelled with a ba and ending with a sin, and he is Ghafiqi the Egyptian. His reliability was established earlier at 6575. Muslim narrated the hadith in the Sahih 2:98, from Zakariya bin Yahya bin Salih the Egyptian, from Mufaddal bin Fadala, with this isnad.