Improper Privilege Management
fof/byobu is a private discussions extension for Flarum forum. Affected versions were found to not respect private discussion disablement by users. Users of Byobu should update the extension to version 1.1.7, where this has been patched. Users of Byobu with Flarum 1.0 or 1.1 should upgrade to Flarum 1.2 or later, or evaluate the impact this issue has on your forum's users and choose to disable the extension if needed. There are no workarounds for this issue.
CWE-269 - Improper Privilege Management
An effective privilege management infrastructure provides valid users with required access and privileges across heterogeneous technology environments. An application with a faulty privilege management infrastructure allows higher than authorized privileges or enables privilege escalation. This can lead to security incidents such as system infiltration, data breach, and complete system takeover.