This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Testpage Overlay
Users of the HAPI FHIR Testpage Overlay 5.0.0 and below can use a specially crafted URL to exploit an XSS vulnerability in this module, allowing arbitrary JavaScript to be executed in the user's browser. The impact of this vulnerability is believed to be low, as this module is intended for testing and not believed to be widely used for any production purposes. (2020-10-08, CVE-2020-24301)
Why Cross-site Scripting can be dangerous
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>