GHSA-65hg-cf3f-5m39 - Highcharts Core: HTML text parsing falls back to unfiltered `innerHTML` during printing
### Impact
When the HTML text parser cannot obtain a document from `DOMParser` because the call throws, it falls back to assigning the raw markup to the `innerHTML` of an element created in the hosting document, and the allow-list is applied only to the resulting DOM afterwards. In Chromium the Trusted Types policy callback that the parser uses throws while a `beforeprint` handler is running, so if the hosting page re-renders the chart from a `beforeprint` handler, every HTML-rendered text option parsed at that moment, such as `useHTML` titles, axis labels and data labels or text set by responsive rules, is inserted unsanitized, and event handlers embedded in that markup run in the origin of the page hosting the chart. Exploitation requires that untrusted data reach the chart configuration, that the hosting page update the chart from a `beforeprint` handler in Chromium, and that printing be started, which the print item of the exporting menu does on its own. Charts built with Highcharts Stock, Maps and Gantt are included, since those ship from the same package as Core.
### Workarounds
**Drop-in fix - for any versions affected (12.0.0-13.0.2).**
Add the below IIFE to run after Highcharts is loaded.
```
((n)=>{n.AST.prototype.parseMarkup=function parseMarkup(t){let e,i=[];t=t.trim().replace(/ style=(["'])/g," data-style=$1");try{e=new DOMParser().parseFromString(tI?tI.createHTML(t):t,"text/html")}catch{}if(!e)try{e=new DOMParser().parseFromString(t,"text/html")}catch{}e||((e=n.doc.implementation.createHTMLDocument("")).body.innerHTML=t);let s=(t,e)=>{let i=t.localName||t.nodeName.toLowerCase(),o={tagName:i};"#text"===i&&(o.textContent=t.textContent||"");let r=t.attributes;if(r){let t={};[].forEach.call(r,e=>{"data-style"===e.name?o.style=tB.parseStyle(e.value):t[e.name]=e.value}),o.attributes=t}if(t.childNodes.length){let e=[];[].forEach.call(t.childNodes,t=>{s(t,e)}),e.length&&(o.children=e)}e.push(o)};return[].forEach.call(e.body.childNodes,t=>s(t,i)),i};})(Highch
HIGH
Severity & confidence
Source severityhigh
Platform severityhigh
Confidenceconfirmed
Exploitationunknown
CVSS-
Affected
VendorshighchartsRed Hataws
Productshighcharts
Reporting sources (3)
GitHub Security Advisories
Red Hat - CVE Feed
NIST NVD - National Vulnerability Database
Timeline & provenance
Published2026-10-28T19:55:22
Last updated2026-10-31T18:01:25
Ingested2026-10-28T19:58:59
FreshnessNEAR-REAL-TIME
Threat typeadvisory
Recommended action
Review the advisory and upgrade affected packages to the first patched version.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
This object is reported by 3 independent sources.
Source type: vendor ยท Original: GitHub Security Advisories