People show this verse 4:23 and say this verse does not forbid cousin marriages. So everyone besides these relatives named can be married.
4:23 “Forbidden for you are
your mothers, and
your daughters, and
your sisters, and
the sisters of your father, and
the sisters of your mother, and
the daughters of your brother, and
the daughters of your sister, and
your foster mothers who suckled you, and
your sisters from suckling, and
the mothers of your women, and
your step-daughters who are in your lodgings from your women with whom you have already consummated the marriage; if you have not consummated the marriage then there is no sin upon you; and
those who were in wedlock with your sons who are from your seed, and
that you join between two sisters except what has already been done.
Allah is Forgiving, Merciful.”
But they neglect the other verse of the Quran 33:50 where Allah said “A PRIVILEGE GIVEN ONLY TO YOU (MUHAMMAD) AND NOT TO THE BELIEVERS” after allowing the cousin marriage for Prophet Muhammad.
Please check the following verse:
COUSIN MARRIAGES ALLOWED ONLY FOR PROPHET MUHAMMAD
33:50 “O prophet, We have made lawful for you the wives to whom you have already given their dowries, and
the one committed to by your oath, as granted to you by Allah; and
THE DAUGHTERS OF THE BROTHERS OF YOUR FATHER, and
THE DAUGHTERS OF THE SISTERS OF YOUR FATHER, and
THE DAUGHTERS OF THE BROTHERS OF YOUR MOTHER, and
THE DAUGHTERS OF THE SISTERS OF YOUR MOTHER-THOSE WHO EMIGRATED WITH YOU. Also,
the believing woman who had decreed herself to the prophet, the prophet may marry her if he wishes, as A PRIVILEGE GIVEN (KHALISATAN) ONLY TO YOU (MUHAMMAD) AND NOT TO THE BELIEVERS.
We have already decreed their rights in regard to their spouses and those who are committed to by their oath. This is to spare you any hardship. Allah is Forgiver, Merciful.”
The Quran explains itself. The cousin marriages were allowed Only for Prophet Muhammad and not for the believers.