I would say not much. If it’s your own personal LAN, and only your devices are on it, and you’re not hosting super sensitive data, then I wouldn’t personally be worried. Just depends on your risk acceptance.
Edit: But if you are hosting sensitive data on an untrusted network, then definitely require a user with a strong password. Also, SMB3 and higher supports encryption (both in Windows and Samba for Linux). Encryption isn’t enabled by default, though. So keep that in mind. Easy to setup on both Windows and Linux.
I would say not much. If it’s your own personal LAN, and only your devices are on it, and you’re not hosting super sensitive data, then I wouldn’t personally be worried. Just depends on your risk acceptance.
Edit: But if you are hosting sensitive data on an untrusted network, then definitely require a user with a strong password. Also, SMB3 and higher supports encryption (both in Windows and Samba for Linux). Encryption isn’t enabled by default, though. So keep that in mind. Easy to setup on both Windows and Linux.