Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS1oODU3LTJnNTYtNDY4Z84AAwwo

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

Impact

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.

Patches

This vulnerability was addressed in v0.4.0.

Workarounds

N/A

Permalink: https://github.com/advisories/GHSA-h857-2g56-468g
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS1oODU3LTJnNTYtNDY4Z84AAwwo
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: over 1 year ago
Updated: about 1 year ago

CVSS Score: 7.6
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

Identifiers: GHSA-h857-2g56-468g, CVE-2023-22461
References:

• https://github.com/mattkrick/sanitize-svg/security/advisories/GHSA-h857-2g56-468g
• https://nvd.nist.gov/vuln/detail/CVE-2023-22461
• https://github.com/mattkrick/sanitize-svg/commit/b107e453ede7b58adcccae74a3e474c012eec85d
• https://github.com/advisories/GHSA-h857-2g56-468g

Repository: https://github.com/mattkrick/sanitize-svg
Blast Radius: 8.9

Affected Packages