CVE-2021-29489 — highcharts
MEDIUMCVE-2021-29489 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in highcharts. A fix is available for highcharts — see the affected versions and patch details below.
Options structure open to Cross-site Scripting if passed unfiltered
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-29489 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
highchartsnpmDescription
Impact
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. Especially when using the useHTML flag, HTML string options would be inserted unfiltered directly into the DOM. When useHTML was false, malicious code could be inserted by using various character replacement tricks or malformed HTML.
If your chart configuration comes from a trusted source like a static setup or pre-filtered HTML (or no markup at all in the configuration), you are not impacted.
Patches
In version 9, the whole rendering layer was refactored to use an DOMParser, an AST and tag and HTML allow-listing to make sure only safe content entered the DOM. In addition, prototype pollution was stopped.
Workarounds
Implementers who are not able to upgrade may apply DOMPurify recursively to the options structure to filter out malicious markup.
References
- Details on the improved Highcharts security
- The AST and TextBuilder refactoring
- The fix for prototype pollution
For more information
If you have any questions or comments about this advisory:
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- For more Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | highcharts | all versions | 9.0.0npm install highcharts@9.0.0 |
Affected Products
highchartshighchartscloud backupnetapponcommand insightnetapponcommand workflow automationnetappsnapcenternetappDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for highcharts, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update highcharts to 9.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29489 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2021-29489 in your dependencies?
Find it across npm, including transitive dependencies.