Discourse vulnerable to multisite DoS by spamming backups

Discourse is an open-source discussion platform. Prior to version 3.0.2 of the stable branch and version 3.1.0.beta3 of the beta and tests-passed branches, a user logged as an administrator can request backups multiple times, which will eat up all the connections to the DB. If this is done on a site using multisite, then it can affect the whole cluster. The vulnerability is patched in version 3.0.2 of the stable branch and version 3.1.0.beta3 of the beta and tests-passed branches. There are no known workarounds.