1. Install WordPress 5.7.2
2. Install and activate Mimetic Books
3. Navigate to Settings >> Mimetic Books API and enter the XSS payload into the Default Publisher ID input field.
4. Click Save Changes.
5. You will observe that the payload successfully got stored into the database and when you are triggering the same functionality at that time JavaScript payload is executing successfully and we are getting a pop-up.
6. Payload Used: "><script>alert(document.cookie)</script>