Input validation vulnerability in SMTP Mail 1.3.20

The email sending feature for WordPress, known as the SMTP Mail plugin, has a security issue that affects all versions up to 1.3.20. This is because the plugin does not properly check for a security code when performing a certain function. This could allow someone without proper access to the website to make changes or actions they are not authorized to do, by tricking the site administrator into clicking on a link.