This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Per Page Add To Head
The Per page add to head WordPress plugin before 1.4.4 is lacking any CSRF check when saving its settings, which could allow attackers to make a logged in admin change them. Furthermore, as the plugin allows arbitrary HTML to be inserted in one of the setting (feature mentioned by the plugin), this could lead to Stored XSS issue which will be triggered either in the backend, frontend or both depending on the payload used. (2021-09-13, CVE-2021-24586)
The Per page add to head WordPress plugin through 1.4.4 does not properly sanitise one of its setting, allowing malicious HTML to be inserted by high privilege users even when the unfiltered_html capability is disallowed, which could lead to Cross-Site Scripting issues. (2021-09-13, CVE-2021-24619)
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>