Sahih al-Bukhari, Book 67, Hadith 126 (In-Book) ⓘ
Narrated Abu Huraira: The Prophet said, "A woman should not fast (optional fasts) except with her husband's permission if he is at home (staying with her).
حَدَّثَنَا مُحَمَّدُ بْنُ مُقَاتِلٍ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم " لاَ تَصُومُ الْمَرْأَةُ وَبَعْلُهَا شَاهِدٌ إِلاَّ بِإِذْنِهِ " .
also referenced under: Hadith 5192 (DarusSalam) & Volume 7, Book 62, Hadith 120 (USC-MSA)