The Prophet ﷺ said, "If a woman gives something (i.e. in charity) from her husband's earnings without his permission, she will get half his reward."

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا أَنْفَقَتِ الْمَرْأَةُ مِنْ كَسْبِ زَوْجِهَا عَنْ غَيْرِ أَمْرِهِ فَلَهُ نِصْفُ أَجْرِهِ