Highcharts: dotted series.keys paths write to Object.prototype

### Impact A dot-separated key path taken from `series.keys` is followed without filtering the individual segments. An attacker who controls `series.keys` and the matching point data can use a path such as `__proto__.polluted` to set arbitrary properties on `Object.prototype`. The resulting properties are visible to all JavaScript running in the page, not only to the chart. No user interaction is required beyond rendering the chart. The injected properties are inert until other code on the page reads them, so consequences 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 ((H)=>{const X = H.isObject;H.Point.prototype.setNestedProperty = function setNestedProperty(t,e,i){let s=i.split(".");return s.some(t=>"__proto__"===t||"constructor"===t)||s.reduce(function(t,i,s,o){let r=o.length-1===s;return t[i]=r?e:X(t[i],!0)?t[i]:{},t[i]},t),t};})(Highcharts); ``` [Live demo & testing](https://jsfiddle.net/BlackLabel/z3rbtm7u/) ### 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 example `npm install [email protected]`. If you load Highcharts from the CDN, use the versioned URLs on code.highcharts.com, for example `https://code.highcharts.com/13.1.1/highcharts.js`. For more on each installation method, see the [installation guide](https://www.highcharts.com/docs/getting-started/installation).

Source published

28 Oct 2026 19:56:18 UTC

Source modified

28 Oct 2026 20:15:06 UTC

Observed here

28 Oct 2026 20:55:42 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:H/SC:L/SI:L/SA:L

Publisher rating · HIGH