BigBlueButton is an open-source virtual classroom. Prior to 3.0.23, BigBlueButton allowed authenticated moderators to inject SQL through the meetingId and userId values used by refreshBreakoutRoomsVisibleForUsers in akka-bbb-apps/src/main/scala/org/bigbluebutton/core/db/BreakoutRoomUserDAO.scala. The method interpolated those values into breakout room visibility queries, allowing arbitrary SQL execution against the application database. This issue is fixed in version 3.0.23.