I am looking for a (best open-source or free but also commercially available) CMS platform that is built similarly to bulletin boards (for example phpBB) but instead of text posts, registered users can upload files that can be rated, commented etc.)

I am aware of the number of board CMSes that have file-database plugins, but that is not what I want. I want to have a system that focuses on the files rather than on the postings.

Or do you have any alternative ideas on solutions to the problem? I need the following functions

• CMS focused on file management
• Files that can be categorized (in a tree-like view for example)
• Comments and ratings can be added to files
• Users that can be provided various rights around the platform (moderation, commenting, exclusion of non-registered users, etc.)
• Users can upload files themselves (for further moderation