Ubaydullah bin Abi Yazid (may Allah have mercy on him) says: I asked Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) about a man who commits zina with a woman: may he marry her? He said: "Yes; then he has attained what is lawful."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13877