Old version of LayerSliger generates spam !

Hello,
The title says it all : For about three months, I got numerous mails from my host, complaining about spams sent from my sites. After many research, I found that the problem was in the LayerSlider plugin of your theme. Here is the entire location of the file causing problems : plugins/layerslider/static/codemirror/mode/smarty/user73.php
The LayerSlider plugin included in the theme is 5.0.2 and the actual version is 5.3.2. But as a lot of people have noticed, it’s impossible to do an automatic update of the plugin.
Could you please provide the code allowing to update LayerSlider to the actual version ?