What is the ruling on the teacher's salary if he fails in his academic duty and gives students the exam questions verbatim to raise their grades, with the administration's knowledge of this?

Whoever does that is an oppressor and a sinner for two reasons: squandering the trust of teaching and failing to perform their work, and helping their students cheat, which harms society. Therefore, they do not deserve their salary because they did not perform the work for which they were hired.