This has been around since the marketplace has been launched and makes whitelisting the marketplace, which should be considered a trustworthy source, a massive security flaw. Considering now avatars are being uploaded to the marketplace and only adding more links to that subdomain, the sooner this gets fixed, the less of a headache one will have to deal with regarding their uploaded goods suddenly vanishing in an attempt to fix a security vulnerability.
And before its asked, no, using a filter should not be required for this. While it could be interesting to have the server check if the script belongs to an actual certified item, all a server owner should have to worry about is "If I whitelist the marketplace, I should be okay."
TLDR: Move unpublished items off mpassets.highfidelity.com and put them somewhere else until they have been published and certified.