What is the ruling on a woman performing الحج without a mahram?

The majority of scholars from the Hanbali and Hanafi schools hold that a mahram is a condition for the obligation of الحج for women. النبي (صلى الله عليه وسلم) said: 'A woman should not travel except with a mahram' (صحيح البخاري 1862, صحيح مسلم 1341). الشيخ ابن باز stated: 'It is not جائز for a woman to perform الحج without a mahram, even if she is with trustworthy women.' However, the Shafi'i and Maliki schools permit a woman to travel with trustworthy women for واجب الحج if no mahram is available. The safest position is to travel with a mahram.