Files is a module for managing files inside spaces and user profiles. Prior to versions 0.16.11 and 0.17.2, insufficient authorization checks allow non-member users to create new folders, up- and download files as a ZIP archive in public spaces. Private spaces are not affected. This issue has been patched in versions 0.16.11 and 0.17.2.
https://github.com/humhub/cfiles/security/advisories/GHSA-rv2x-7qwp-2hf4
https://github.com/humhub/cfiles/commit/75698f8e8f360cea470f0e9f264015b697ab4c09