Wp Page Builder Cross-site Scripting

The WP Page Builder WordPress plugin through 1.2.8 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup). (2022-12-05, CVE-2022-3830)

Multiple Auth. (author+) Stored Cross-Site Scripting (XSS) vulnerabilities in WP Page Builder plugin <= 1.2.6 on WordPress. (2022-11-18, CVE-2022-40963)

The editor of the WP Page Builder WordPress plugin before 1.2.4 allows lower-privileged users to insert unfiltered HTML, including JavaScript, into pages via the “Raw HTML” widget and the “Custom HTML” widgets (though the custom HTML widget requires sending a crafted request - it appears that this widget uses some form of client side validation but not server side validation), all of which are added via the “page_builder_data” parameter when performing the “wppb_page_save” AJAX action. It is also possible to insert malicious JavaScript via the “wppb_page_css” parameter (this can be done by closing out the style tag and opening a script tag) when performing the “wppb_page_save” AJAX action. (2021-04-05, CVE-2021-24208)

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>