In what cases is backbiting permissible?

Question:
The verses that summarize the cases in which backbiting is permissible: is everything mentioned in them correct?

Answer:
And Allah is the Exalted.
Sin is not backbiting in six cases:
For the one seeking redress, the one identifying, and the one warning,
And for the one exposing open sinfulness, the one seeking a ruling, and the one
Who seeks assistance in removing a wrong.
All of these are clear:
The one identifying: the scholars identified the criticized narrators.
And the one warning against the people of innovation is likewise.
And the one advising is known likewise.
The one exposing open sinfulness, and the one seeking a ruling: like the woman who said: O Messenger of Allah, Abu Sufyan is a stingy man, seeking a ruling.
And the one seeking assistance in removing a wrong, and cooperating to remove the wrong present in a certain place.