Discourse is an open source platform for community discussion. In affected versions users who disable chat in preferences could still be reachable in some cases. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should disable the chat plugin within site settings.
The product does not preserve permissions or incorrectly preserves permissions when copying, restoring, or sharing objects, which can cause them to have less restrictive permissions than intended.