Is it permissible for a veiled woman to wear open-toed shoes without socks due to the heat?

A woman must cover her feet completely in front of non-mahram (definition) men, based on the Prophet's (peace and blessings be upon him) saying to Umm Salamah when she asked him about women's trains: "They should let it down a cubit and no more," so that their feet are not exposed. Ahmad ibn Hanbal was of the view that everything of a woman is 'awrah, even her fingernail. Therefore, it is not permissible for a woman to wear shoes that expose any part of her foot unless she wears something to cover it, such as socks, or lengthens her garment. She must fear Allah and remember His saying, the Almighty: "Say, 'The Fire of Hell is more intense in heat' if they only understood."