Hi!
@gn_themes: first of all, thank you for the great plugin. I truly believe this is a nice tool for WP and I am grateful to you for dedicating your time to developing this for the community.
Having said that, I had emailed you long time ago about the timthumb vulnerability (which I unfortunately found out about the hard way as one of the sites I managed got hacked) and never received a reply.
It should not be so hard to keep updated with this issue, which is now known since months as a known security flaw.
Currently, you’re using v2.8.5, which should be safe (v prior to 2.8.2 are considered not safe), but the latest version is 2.8.9 and it seems to run without issues with Shortcodes Ultimate.
At any rate, a free plugin is available that scans for timthumb library (there could be multiple copies in case there is more than 1 plugin using it) and can also automatically upgrade it to the latest version. You can search on the repository for “Timthumb scanner”.
Hope this helps.