GHSA-gfvx-2c2g-38wq - Highcharts: series column construction writes to Object.prototype
### Impact
When series columns are built from point objects, the point option keys are used directly as data column ids, so the write that populates a column reaches `Object.prototype` and the `Object` constructor. Keys named `__proto__` and `constructor` survive `JSON.parse` as own enumerable properties, so an attacker who controls the point objects can set integer-keyed properties on `Object.prototype`, one per point index, to values of their choosing. Named properties cannot be reached this way. The integer keys still affect every object in the page: reading an out-of-range index on any array or plain object returns the attacker's value, and `for...in` over any object yields the injected keys, so unrelated code can take branches it should not using attacker-supplied data, and rendering can fail as a side effect. The properties remain in place once the chart has been built, and no user interaction is required beyond rendering the chart.
Consequences beyond disruption depend on the consuming application.
### Workarounds
Drop-in fix - for any versions affected (6.1.0-13.0.2).
Add the below IIFE to run after Highcharts is loaded.
```javascript
;!function(t){if(t&&t.Point&&!t.Point.prototype.protoPollutionPatched){var o=t.Point.prototype,r=o.optionsToObject,e=o.setNestedProperty,n=Object.prototype.hasOwnProperty;o.optionsToObject=function(t){if(t&&"object"==typeof t&&!Array.isArray(t)&&(n.call(t,"__proto__")||n.call(t,"constructor"))){var o={};for(var e in t)n.call(t,e)&&!c(e)&&(o[e]=t[e]);t=o}return r.call(this,t)},o.setNestedProperty=function(t,o,r){return String(r).split(".").some(c)?t:e.call(this,t,o,r)},o.protoPollutionPatched=!0}function c(t){return"__proto__"===t||"constructor"===t}}(Highcharts);
```
[Live demo & testing](https://jsfiddle.net/BlackLabel/nopc6vhj/)
### Obtaining the patched version
The patched releases are available from all the usual distribution channels. With npm, upgrade the affected package to the patched version listed above, for exam
HIGH
Severity & confidence
Source severityhigh
Platform severityhigh
Confidencehigh
Exploitationunknown
CVSS-
Affected
Vendorshighcharts
Productshighcharts
Reporting sources (2)
GitHub Security Advisories
NIST NVD - National Vulnerability Database
Timeline & provenance
Published2026-10-28T19:56:13
Last updated2026-10-31T18:01:25
Ingested2026-10-28T19:58:58
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
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: vendor ยท Original: GitHub Security Advisories