A missing access control check in Nextcloud Server < 18.0.1, < 17.0.4, and < 16.0.9 causes hide-download shares to be downloadable when appending /download to the URL.

Nextcloud server is an open source home cloud implementation. In affected versions a missing scope validation allowed users to create workflows which are designed to be only available for administrators. Some workflows are designed to be RCE by invoking defined scripts, in order to generate PDFs, invoking webhooks or running scripts on the server. Due to this combination depending on the available apps the issue can result in a RCE at the end. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. Users unable to upgrade should disable app workflowscripts and workflowpdfconverter as a mitigation.

A too small set of random characters being used for encryption in Nextcloud Server 18.0.4 allowed decryption in shorter time than intended.

An Insecure direct object reference vulnerability in Nextcloud Server 18.0.2 allowed an attacker to remote wipe devices of other users when sending a malicious request directly to the endpoint.