How insecure is a public export = yes (hidden) smb share to ransomware on the network?

If I set and SMB share to public (a requirement of a specific application I am running), but set export to yes (hidden), how insecure is the share on my home network?

I know that if someone knows the network path they can access the share and do what ever they want to the files. However, if someone does not know the network share there should be no problem right?

My question is mostly with respect to protection from ransomware that finds and encrypts all files it can locate on a network. If a user at a network computer does not know of the share and has never accessed the share (and the share if hidden), could ransomware on that networked computer search and find this share or is this not possible? Is there a mechanism for a computer to find a hidden share other than knowing typing the specific file path?

For context, I'm not worried about these files being accessed and read by others (they are encrypted) but I am worried about them being locked my ransomware someone else accidently introduces into the home network).

Thanks!