The Tables and Charts Manager for WordPress plugin, called The Visualizer, is not safe to use. This is because it has a vulnerability called Stored Cross-Site Scripting. This means that if someone with the right access uses the Import Data From File feature, they can put harmful code into the plugin. This can happen in any version of the plugin up to version 3.11.8. This can be done by injecting web scripts into certain pages, which will then run whenever a person visits the page.