Hello,
If you read this topic attentively http://marketblog.envato.com/general/plugin-vulnerability/ you know that recommended version is 4.2 or higher. Legenda 2.4 includes Revolution Slider v. 4.6. Also we have sent it to you.
If you updated your theme, always check if you updated the included plugins too. Last versions of plugins you may find in theme package (legenda/framework/plugins).
Don’t worry, Legenda theme is compatible with WordPress 4.0.
You can download a new version of the Legenda Theme (2.4) in Downloads area of your account on themeforest.
Regards,
Robert Hall.