Is it forbidden or permissible to sit unveiled in front of one's paternal aunt through fosterage?

Your mother's sister through fosterage is your maternal aunt through fosterage, and she is a mahram to you, for the Prophet, peace and blessings be upon him, said: "What becomes unlawful by lineage becomes unlawful by fosterage." And for Allah's saying: "Prohibited to you are your mothers, your daughters, your sisters, your paternal aunts, and your maternal aunts." Therefore, it is permissible for you to sit in front of her while she is not veiled.