This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Svg Support
The SVG Support plugin for WordPress defaults to insecure settings in version 2.5 and 2.5.1. SVG files containing malicious javascript are not sanitized. While version 2.5 adds the ability to sanitize image as they are uploaded, the plugin defaults to disable sanitization and does not restrict SVG upload to only administrators. This allows authenticated attackers, with author-level privileges and higher, to upload malicious SVG files that can be embedded in posts and pages by higher privileged users. Additionally, the embedded JavaScript is also triggered on visiting the image URL, which allows an attacker to execute malicious code in browsers visiting that URL. (2022-11-16, CVE-2022-4022)
The SVG Support WordPress plugin before 2.5 does not properly handle SVG added via an URL, which could allow users with a role as low as author to perform Cross-Site Scripting attacks (2022-09-26, CVE-2022-1755)
The SVG Support WordPress plugin before 2.3.20 does not escape the "CSS Class to target" setting before outputting it in an attribute, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed. (2022-02-01, CVE-2021-24686)
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>