Fatwa ID: 05015
Answered by: Maulana Muhammad Asadullah Anwar Adam
Is it haram for a woman to show her hair fully to a woman?
In the name of Allah, the Most Gracious, the Most Merciful
The awrah of a woman with another woman is the area between the navel and the knee,  thus it is permissible as a woman to show another woman her hair fully.
Only Allah knows best
Written by Maulana Muhammad Asadullah Anwar Adam
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Qudoori page 848, Maktabul Bushra print