{"id":"CVE-2026-118249","aliases":["GHSA-gfvx-2c2g-38wq"],"url":"https://o3.security/vulnerability/CVE-2026-118249","summary":"Highcharts: series column construction writes to Object.prototype","details":"### Impact\nWhen 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.\n\nConsequences beyond disruption depend on the consuming application.\n\n### Workarounds\nDrop-in fix - for any versions affected (6.1.0-13.0.2).\nAdd the below IIFE to run after Highcharts is loaded.\n\n```javascript\n;!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);\n```\n\n[Live demo & testing](https://jsfiddle.net/BlackLabel/nopc6vhj/)\n\n### Obtaining the patched version\nThe 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 highcharts@13.1.0`. If you load Highcharts from the CDN, use the versioned URLs on code.highcharts.com, for example `https://code.highcharts.com/13.1.0/highcharts.js`. For more on each installation method, see the [installation guide](https://www.highcharts.com/docs/getting-started/installation).","published":"2026-10-28T17:57:18.323Z","modified":"2026-10-29T02:48:31.522825085Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"highcharts","fixedVersion":"13.1.0"}],"fix":{"url":"https://github.com/highcharts/highcharts/commit/d3357705c8f348904441327e32f50ab528c3a205","label":"highcharts/highcharts@d335770"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/118xxx/CVE-2026-118249.json"},{"type":"FIX","url":"https://github.com/highcharts/highcharts/commit/d3357705c8f348904441327e32f50ab528c3a205"},{"type":"FIX","url":"https://github.com/highcharts/highcharts/pull/25321"},{"type":"WEB","url":"https://github.com/highcharts/highcharts/releases/tag/v13.1.0"},{"type":"ADVISORY","url":"https://github.com/highcharts/highcharts/security/advisories/GHSA-gfvx-2c2g-38wq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118249"},{"type":"PACKAGE","url":"https://github.com/highcharts/highcharts"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-29T02:48:31.522825085Z"}}