Stop users from being able to grant permissions on their media to other users

I’ve setup a user with the very minimal permissions. They can upload their own new media and place that media in a handful of pre-built layouts for which they’ve been shared/permitted access.

When they upload their own media though, they have the option to grant permissions (view,edit,delete) to absolutely everyone. Have I missed the setting that would prohibit them from granting permissions to all and sundry? The issue is I don’t want random media turning up in other users’ libraries, nor do I particularly want every user to be privy to the usernames of every other user using the CMS.

having same issue, did you find solution ?

It shouldn’t be a problem in 1.8 series.