The Times When Backbiting and Criticizing is Permissible
According to The ‘Ulama of Islam
Imam an-Nawawi stated:
You should know that ghibah (backbiting) is allowed for genuine Divinely Legislated reasons and it is not possible to do it except with these reasons, they are six which are:
1. Complaining when wronged.
2. When seeking help in order to change an evil and to make a sinful person return to the truth.
3. When seeking a fatwa.
4. When warning Muslims from evil and giving them advice.
5. That the person being spoken about is doing the sin or innovation openly.
6. When defining a person if the person is well-known by a particular attribute such as al-‘A’ma (the blind one), al-‘A’raj (the one with the limp), al-Asamm (the deaf), this is permissible in order to define them.
“Be A Serious Salafi” pg.108