The contract address is a hash generated from the wallet address that deploys it plus the
nonce. That's why even if you deploy the same contract on multiple chains, the contract address will most likely be different.
https://ethfiddle.com/lOvRUBOJso - this is a simple fiddle, but if you click
create multiple times, you'll see how the contract address changes each time.
That said, I think you have a misunderstanding on how contracts work. The person who calls the functions are the ones signing and paying for the transaction. So just because multiple contracts exist on different chains, doesn't mean that the private/public key pair of the wallet that deployed it is compromised.