CVE-2023-22461

@mattkrick/sanitize-svg vulnerable to Cross-Site Scripting (XSS)

Workarounds

N/A

The sanitize-svg package uses a deny-list-pattern to sanitize SVGs to prevent cross-site scripting (XSS). In doing so, literal <script>-tags and on-event handlers were detected:

[...]
  const svgEl = div.firstElementChild!
  const attributes = Array.from(svgEl.attributes).map(({ name }) => name)
  const hasScriptAttr = !!attributes.find((attr) => attr.startsWith('on'))
  const scripts = svgEl.getElementsByTagName('script')
  return scripts.length === 0 && !hasScriptAttr ? svg : null
[...]

There are more ways to embed JavaScript in XML files.

Anchor Tag (requires user to click link):

<svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <a href="javascript:alert(document.domain)">
    <text x="50" y="50" text-anchor="middle">Lauritz</text>
  </a>
</svg>

Foreign Object Tag (no user interaction required):

<svg width="500" height="500" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
        <text x="20" y="35">Lauritz</text>
        <foreignObject width="500" height="500">
                <iframe xmlns="http://www.w3.org/1999/xhtml" src="javascript:confirm(document.domain);" width="400" height="250"/>
        </foreignObject>
</svg>

As a result, downstream software that relies on sanitize-svg and expects resulting SVGs to be safe, may be vulnerable to XSS. We are aware of at least one downstream project for which this vulnerability had security implications.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2023-22461 has a CVSS score of 7.6 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.4.0); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

This vulnerability was addressed in v0.4.0.

1. What is CVE-2023-22461? CVE-2023-22461 is a high-severity cross-site scripting (XSS) vulnerability in @mattkrick/sanitize-svg (npm), affecting versions <= 0.3.1. It is fixed in 0.4.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2023-22461? CVE-2023-22461 has a CVSS score of 7.6 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of @mattkrick/sanitize-svg are affected by CVE-2023-22461? @mattkrick/sanitize-svg (npm) versions <= 0.3.1 is affected.
4. Is there a fix for CVE-2023-22461? Yes. CVE-2023-22461 is fixed in 0.4.0. Upgrade to this version or later.
5. Is CVE-2023-22461 exploitable, and should I be worried? Whether CVE-2023-22461 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-22461 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-22461? Upgrade @mattkrick/sanitize-svg to 0.4.0 or later.