Is it permissible to perform Umrah and Hajj without the husband's permission, when he has not provided for or known anything about his wife and children for six years?

If a husband abandons his wife and refuses to spend on her without a legitimate Sharia reason, she is permitted to deny him access to herself and prevent him from enjoying her. Similarly, she is allowed to leave without his permission for her needs, such as performing Hajj or Umrah with a mahram. As Ibn Qudamah said: "If she agrees to remain with that – meaning with the lack of spending – she is not obliged to allow him enjoyment; because he has not delivered its compensation to her." And Ibn Uthaymeen mentioned: "If he withholds her maintenance, does his right fall away? Yes, (AND IF YOU PUNISH [AN ENEMY], PUNISH WITH ONLY THAT WITH WHICH YOU WERE AFFLICTED) An-Nahl/126. So, if the husband withholds maintenance from his wife, she has the right to deny herself to him."