Versions of Webmin prior to 1.997 have a Critical vulnerability (CVSS3 score of 9.8). This is an authenticated vulnerability so in my case as the only Webmin user I'm not worried about it. Others may have more Webmin users so might be at a greater risk. I wondered whether it's worth applying an upgrade to the latest Webmin version?
That would at least stop my vulnerability scanner from telling me about some critical bugs!
I tried your Media Server.OVA and noticed that there is the version:
Server: mediaserver
Version: 10.7.2
as I am new with all this server stuff, I don't know if this is a docker or other installation ad there are surely different ways to get the latest version
I think I originally proposed this like 2 or 3 years ago, I can't find the thread but at one point my account on the forum got accidentally deleted so I'm guessing that's where it went.