CVE-2025-61906: low-severity vulnerability in opencast

Opencast is a free, open-source platform to support the management of educational audio and video content. Prior to Opencast 17.8 and 18.2, in some situations, Opencast's editor may publish a video without notifying the user. This may lead to users accidentally publishing media not meant for publishing, and thus possibly exposing internal media. This risk of this actually impacting someone is very low, though. This can only be triggered by users with write access to an event. They also have to use the editor, which is usually an action taken if they want to publish media and not something users would use on internal media they do not want to publish. Finally, they have to first click on "Save & Publish" before then selecting the "Save" option. Nevertheless, while very unlikely, this can happen. This issue is fixed in Opencast 17.8 and 18.2.