Kendo Ui Cross-site Scripting

Cross-site scripting (XSS) vulnerability in Progress Kendo UI Editor v2018.1.221 allows remote attackers to inject arbitrary JavaScript into the DOM of the WYSIWYG editor because of the editorNS.Serializer toEditableHtml function in kendo.all.min.js. If the victim accesses the editor, the payload gets executed. Furthermore, if the payload is reflected at any other resource that does rely on the sanitisation of the editor itself, the JavaScript payload will be executed in the context of the application. This allows attackers (in the worst case) to take over user sessions. (2018-09-28, CVE-2018-14037)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>