You can protect yourself by upgrading to the latest version of Akismet 3.1.5, under Dashboard → Updates in your WordPress dashboard.
We have released VaultPress 1.7.8 which will protect your site from this vulnerability. We have also attempted to automatically upgrade our customers to this newer version of VaultPress and Akismet. You can verify that you’re running the latest version of Akismet 3.1.5 on the Plugins page in your WordPress dashboard.
As always, if you have any questions, drop us a line!