Highcharts JS is a JavaScript charting library based on SVG. In Highcharts versions 8 and earlier, the chart options structure was not systematically filtered for XSS vectors. The potential impact was that content from untrusted sources could execute code in the end user's browser. The vulnerability is patched in version 9. As a workaround, implementers who are not able to upgrade may apply DOMPurify recursively to the options structure to filter out malicious markup.