Nextcloud Server's read-only users can restore old versions

Nextcloud Server is a self hosted personal cloud system. An attacker with read-only access to a file is able to restore older versions of a document when the files_versions app is enabled. It is recommended that the Nextcloud Server is upgraded to 26.0.12, 27.1.7 or 28.0.3 and that the Nextcloud Enterprise Server is upgraded to 23.0.12.16, 24.0.12.12, 25.0.13.6, 26.0.12, 27.1.7 or 28.0.3.