The application is vulnerable to clickjacking.

Clickjacking is when an attacker uses multiple transparent or opaque layers to trick a user into clicking on a button or link on another page when they were intending to click on the the top level page. Thus, the attacker is "hijacking" clicks meant for their page and routing them to another page, most likely owned by another application, domain, or both.

Proof of concept :

Create a HTML file with the below content. You will be able to verify the issue.

<title>Clickjack test page</title>

You’ve been clickjacked!

<iframe sandbox="allow-scripts allow-forms" src="https://demo.gleezcms.org/" style="width:100%;height:90%"></iframe>