Secure category names leaked via user activity export in Discourse

Discourse is an open source discussion platform. Versions 2.8.2 and prior in the stable branch, 2.9.0.beta3 and prior in the beta branch, and 2.9.0.beta3 and prior in the tests-passed branch are vulnerable to a data leak. Users can request an export of their own activity. Sometimes, due to category settings, they may have category membership for a secure category. The name of this secure category is shown to the user in the export. The same thing occurs when the user's post has been moved to a secure category. A patch for this issue is available in the main branch of Discourse's GitHub repository and is anticipated to be part of future releases.