Opencast is a free, open-source platform to support the management of educational audio and video content. Prior to versions 19.7 and 20.2, the default security configuration in etc/security/mhdefaultorg.xml accepts a client-selected JSESSIONID from the ;jsessionid= URL path parameter and does not replace it when the victim logs in. An unauthenticated attacker can send a crafted link to a victim whose browser has no active Opencast session cookie, wait for the victim to authenticate, and then reuse the known identifier as the victim's authenticated session. This can expose the victim's data and actions and can produce full administrative account takeover when the victim is an administrator. This issue is fixed in versions 19.7 and 20.2.

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.

Opencast is a free, open-source platform to support the management of educational audio and video content. In version 18.0 and versions before 17.7, the protections against path traversal attacks in the UI config module are insufficient, still partially allowing for attacks in very specific cases. The path is checked without checking for the file separator. This could allow attackers access to files within another folder which starts with the same path. This issue has been fixed in versions 17.7 and 18.1. To mitigate this issue, check for folders that start with the same path as the ui-config folder.

Opencast 2.3.2 and older versions are vulnerable to script injections through media and metadata in the player and media module resulting in arbitrary code execution, fixed in 2.3.3 and 3.0.