Is it safe to provide previous I-797 to a new To-Be employer?

An employer is interested to file a cap exempt visa on my previous visa. However, before talking any further, the To-Be employer is first insisting me to send a scanned copy of previous I-797.

Would the employer able to file a visa for someone else through my cap number? Is it safe to send a scanned copy of my previous I-797 to that employer without having negotiations done?

For filing in cap exempt/ tranfer the new employer might need the scanned copy of I-797. I don’t think they can misuse this copy. It depends on the company with whom are you approaching.