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.
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
Access control involves the use of several protection mechanisms such as:
When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses: