The World Federation One Stop Fiqh

Ruling 386

If after performing prayers a person who had become junub doubts whether he had performed ghusl or not, the prayers he performed are valid; however, for future prayers he must perform ghusl. If after prayers he has a minor occurrence, it is necessary for him also to perform wuḍūʾ; and if there is time, he must, based on obligatory precaution, repeat the prayers he had performed.