{"id":"CVE-2026-118249","aliases":["GHSA-gfvx-2c2g-38wq"],"title":"Highcharts: series column construction writes to Object.prototype","summary":"Highcharts: series column construction writes to Object.prototype","severity":"high","cvss":7.2,"cwe":["CWE-1321"],"vendor":"highcharts","product":"highcharts","ecosystem":"npm","affected":["highcharts >= 13.0.0, <= 13.0.2"],"patched":["highcharts 13.1.0"],"published":"2026-10-28","updated":"2026-10-28","sourceUpdated":"2026-10-28T19:56:15Z","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-gfvx-2c2g-38wq","references":[{"url":"https://github.com/highcharts/highcharts/security/advisories/GHSA-gfvx-2c2g-38wq"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118249"},{"url":"https://github.com/highcharts/highcharts/pull/25321"},{"url":"https://github.com/highcharts/highcharts/commit/d3357705c8f348904441327e32f50ab528c3a205"},{"url":"https://github.com/highcharts/highcharts/releases/tag/v13.1.0"},{"url":"https://github.com/advisories/GHSA-gfvx-2c2g-38wq"}],"tags":["ghsa","npm","cve.org"],"cvssVector":"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","cvssSource":"cna","ingestedAt":"2026-10-28T18:15:46.375Z","slug":"CVE-2026-118249","body":"## Overview\n\n### 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).\n\n## Affected packages\n\n- `highcharts >= 13.0.0, <= 13.0.2`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `highcharts 13.1.0`","depth":"twilight","depthScore":40,"depthScoreParts":{"impact":39.6,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}