Essentially, if I create an asset, I understand if I am reliable for any damages caused to the end-user. However, does this apply if the asset is modified by the end user? I would not believe so.
Also no lawyer, but I’d still want to know how you are distributing the product, and if you are charging for it. Going through the unity asset store, for example, introduces a whole bunch of legal stuff, like an ELUA that defines exactly your liability. Asset Store Terms of Service and EULA (check out 6- indemnification)
If a free product, distributed yourself: lots of public licensing templates like GNU, also define your liability strictly.
You are going to want SOME kind of licensing on your product, and that should spell out exactly what your liability is, and is not. Make sure it is available for potential customers to read, before they buy the product.
I wouldn’t think you’re liable any more due to asset being modified by other party. You have no control over what the end uses does that could potentially cause damage. I think would need to put in a notice or such that not liable for end user modifications. But I could be wrong.
The asset as is should not cause damage if they followed directions correctly. If you know of a reason this would cause a problem warn the user some how.
I am not a legal expert but common seance says it would not be your liability.