All software has bugs. Sometimes bugs let you do things you weren’t intended to be able to do (e.g. access data on a NAS without knowing the login password). Your NAS might have a bug that hasn’t been discovered (or publicized yet) or hasn’t been fixed yet.
If you put your NAS on the internet, you give “bad guys” am opportunity to exploit those bugs to get your data or to use your NAS as a jumping off spot to attack other things inside your home network.
All software has bugs. Sometimes bugs let you do things you weren’t intended to be able to do (e.g. access data on a NAS without knowing the login password). Your NAS might have a bug that hasn’t been discovered (or publicized yet) or hasn’t been fixed yet.
If you put your NAS on the internet, you give “bad guys” am opportunity to exploit those bugs to get your data or to use your NAS as a jumping off spot to attack other things inside your home network.