Why do you think it's not your own? Transactions don't have a 'from' address, it's possible etherscan made a mistake in guessing who it's from. But more likely it is one of your addresses, perhaps a different one to the one you thought, such as a change address. Or if you're using an exchange or web wallet, it might just be from another one of the UTXOs that exchange/wallet has, not deposited to you