Please update your copy of WP-Cumulus to 1.23 asap. For most users it should only take two clicks.
The should not affect how WP-Cumulus works on WordPress blogs. But there have been a number of ports and other projects that use the Flash movie. I urge the authors of those projects to examine the new Flash movie, and see if it still works in/with their product. The exploit is not unique to WordPress, and they may need to modify the security check to fit their project.