Easy Contact Form Pro < 126.96.36.199 - Authenticated Stored Cross-Site Scripting (XSS)
The plugin did not properly sanitise the text fields (such as Email Subject, Email Recipient, etc) when creating or editing a form, leading to an authenticated (author+) stored cross-site scripting issue. This could allow medium privilege accounts (such as author and editor) to perform XSS attacks against high privilege ones like administrator.
It is unclear if all fields have been sanitised, or just the reported one from the original advisory available in the references
Proof of Concept
As an author, editor or admin, create/edit a form and add the following payload in the 'Email Subject" field "><svg/onload=alert(/XSS/)>