2,178. Converts Marrying Mamzerim
Hilchos Issurei Biah 15:8
If a convert woman marries a convert man and they have a son, he is permitted to marry a mamzeres even though he was conceived and born after his parents were Jewish. This applies to all of his descendants until the connection to conversion is forgotten and it’s not known that he comes from converts. Once this happens, he will be prohibited to marry a mamzeres. The same rules apply to converts and to freed servants.
Hilchos Issurei Biah 15:9
If a convert marries a woman who was born Jewish, or a man born Jewish marries a convert woman, their son is Jewish in all regards and may not marry a mamzeres.