I've always kept Excel (the only Office app I use) up to date, but hand in hand with that, I've always wondered what security vulnerabilities could exist in an app that's neither connected to the Internet nor generating files that I intend to transmit over it.
The prime danger is NOT in connecting the app to the internet or generating files you intend to transmit over it. It lies in opening files you have
received over the internet that contain exploits which can take advantage of vulnerabilities in the app to expose your system to a rich variety of exploits.
Because Office apps contain their own scripting language
Visual Basic for Applications (VBA) they have been used to disseminate malware if not being malware themselves. Needless to say Windows is most vulnerable to such Office exploits, but there have been at least attempts at exploits that might attack MacOS as well.
