It's not safe to open doc emails attachements in Microsoft Office, because of evil macros. Is it safe to open same file in Libre office or does it also execute macros?
By design, LibreOffice will not execute macros that are not signed or are signed by an untrusted party without prompting the user and giving a security warning.
I am not aware of any exploits that override that, you may be alright.
It is still good practice not to accept documents from strangers, however.