What are the consequences of a woman marrying another man two days after her divorce, without observing the 'iddah, and she is now a mother to a child from the second husband?

Marriage during the iddah (waiting period) is null and void by the consensus of jurists, and the couple must be separated immediately. If the marriage was due to ignorance, it is considered a shubhāt (doubtful) marriage, and the children are attributed to the husband. However, if it was done with knowledge of its unlawfulness, it is considered zina (fornication), and the children are attributed to the mother. If one party was aware and the other ignorant, the sin falls upon the one who was aware. If the father was aware, the children are not attributed to him but to their mother.

After separation, they may marry each other again with a new contract, provided that the woman completes her iddah from the first husband, as the period of the shubhāt marriage is not counted as part of the iddah. As for marriage with knowledge (zina), the iddah is not interrupted, and the original iddah would have ended, but she must observe an iddah from the zina.

They may marry each other again with a new contract according to the Hanafis and Shafi'is, and as chosen by Ibn Taymiyyah, while the Malikis and Hanbalis hold that she becomes permanently unlawful to him. If the woman wishes to marry someone else other than the man she married during her iddah, she must observe two iddahs: one from the first (husband) and another from the second, and there is no intermingling between the two iddahs according to the majority of scholars, contrary to the Hanafis.