The Contact Builder plugin contains a security hole that allows hackers to send emails post officeu spam/phishing for account of websites that use it, according to a announcement the company's.
The issue was first reported by some members of the company support forum and soon after by the WordFence team. 
According to the company's announcement, immediate measures have been taken to fix all the security gaps and one has been released information.
If useste Builder Contact on the previous version 1.4.6, you should update to the latest version immediately.
If you have the old version of Builder Contact installed on your server but have not activated it, delete it or replace it with the latest version (do not leave the vulnerability on the server, even if you do not have it enabled).
If your subscription has expired and Builder Contact cannot be updated, contact the company and they will give you the new version for free with a extension 3 months subscription.
