Being married to paternal and maternal cousins at the same time
Two sisters married two brothers and each of them gave birth to a girl. The daughters therefore became both maternal and paternal cousins. I have married one of them, is it permissible for me to marry the other daughter?
If the situation is as you have mentioned, it is permissible for you to marry the other daughter. The fact the each of the two daughters is the paternal and the maternal cousin of the other does not prohibit marriage to the two of them at same the time. May Allah grant us success. May peace and blessings of Allah be upon our Prophet Muhammad, his family, and Companions.