CVE-2026-116796

Highcharts Core: javascript: URL in an xlink:href attribute survives text filtering and reaches exported charts

!function(t){var e=t&&t.AST;if(e&&"function"==typeof e.filterUserAttributes&&!e.xlinkHrefPatched){var r=e.filterUserAttributes,n=Object.prototype.hasOwnProperty;e.filterUserAttributes=function(t){return t&&n.call(t,"xlink:href")&&!o(t["xlink:href"])&&delete t["xlink:href"],r.call(this,t)},e.xlinkHrefPatched=!0}function o(t){var r=e.allowedReferences||["https://","http://","mailto:","/","../","./","#"];return"string"==typeof t&&r.some(function(e){return 0===t.indexOf(e)})}}(Highcharts);

The filter applied to markup in text options checks href, src and a few similar attributes against an allowed-scheme list, but accepts xlink:href without that check, so an SVG anchor whose xlink:href is a javascript: URL passes the filter, whether or not the option is rendered with useHTML. In the live page the attribute is written without the XLink namespace, so browsers do not treat the anchor as a link there.

The attribute is preserved verbatim in the chart's serialised output: the SVG produced by the exporting module, including the default SVG download, declares the XLink namespace and contains the anchor, and so does the markup of the chart container. Any document that parses that output again, such as the downloaded SVG opened in a browser or a page that inlines exported or server-rendered chart markup, then holds a working link, and an attacker who controls the chart configuration can thereby run script in the origin of that document when a user activates the link.

Exploitation requires that untrusted data reach a text option such as the title, that the chart be exported or its markup be serialised and parsed again, and that a user activate the link.

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.

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1. What is CVE-2026-116796? CVE-2026-116796 is a high-severity cross-site scripting (XSS) vulnerability in highcharts (npm), affecting versions >= 10.3.2, < 11.4.9. It is fixed in 11.4.9, 12.6.2, 13.1.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. Which versions of highcharts are affected by CVE-2026-116796? highcharts (npm) versions >= 10.3.2, < 11.4.9 is affected.
3. Is there a fix for CVE-2026-116796? Yes. CVE-2026-116796 is fixed in 11.4.9, 12.6.2, 13.1.1. Upgrade to this version or later.
4. Is CVE-2026-116796 exploitable, and should I be worried? Whether CVE-2026-116796 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
5. What actually determines whether CVE-2026-116796 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.
6. How do I fix CVE-2026-116796?
   • Upgrade highcharts to 11.4.9 or later
   • Upgrade highcharts to 12.6.2 or later
   • Upgrade highcharts to 13.1.1 or later

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