What is the ruling on a woman performing Hajj without her husband’s permission?

The obligatory Hajj is obligatory if the conditions are met, and the husband’s permission is not one of the conditions. The husband is not permitted to prevent his wife from performing the obligatory Hajj. Whenever she finds a mahram to travel with after the conditions are met, she must perform Hajj even if her husband does not give permission, because there is no obedience to a creature in disobedience to the Creator.