CVE-2026-118249

Highcharts JS is a JavaScript charting library based on SVG. From 13.0.0 until 13.1.0, Highcharts builds series data columns by using point option keys directly as column IDs. Own enumerable proto and constructor keys from parsed point objects can therefore direct integer-indexed writes to Object.prototype or the Object constructor. The inherited values affect reads and for-in enumeration across the page and can disrupt rendering or alter consuming application behavior without user interaction beyond rendering the chart. This issue is fixed in 13.1.0.

Highcharts JS is a JavaScript charting library based on SVG. From 13.0.0 until 13.1.0, Highcharts builds series data columns by using point option keys directly as column IDs. Own enumerable proto and constructor keys from parsed point objects can therefore direct integer-indexed writes to Object.prototype or the Object constructor. The inherited values affect reads and for-in enumeration across the page and can disrupt rendering or alter consuming application behavior without user interaction beyond rendering the chart. This issue is fixed in 13.1.0.

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.

;!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

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/13.1.0/highcharts.js. For more on each installation method, see the installation guide.

Highcharts JS is a JavaScript charting library based on SVG. From 13.0.0 until 13.1.0, Highcharts builds series data columns by using point option keys directly as column IDs. Own enumerable proto and constructor keys from parsed point objects can therefore direct integer-indexed writes to Object.prototype or the Object constructor. The inherited values affect reads and for-in enumeration across the page and can disrupt rendering or alter consuming application behavior without user interaction beyond rendering the chart. This issue is fixed in 13.1.0.

Highcharts JS is a JavaScript charting library based on SVG. From 13.0.0 until 13.1.0, Highcharts builds series data columns by using point option keys directly as column IDs. Own enumerable proto and constructor keys from parsed point objects can therefore direct integer-indexed writes to Object.prototype or the Object constructor. The inherited values affect reads and for-in enumeration across the page and can disrupt rendering or alter consuming application behavior without user interaction beyond rendering the chart. This issue is fixed in 13.1.0.

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.

;!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

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/13.1.0/highcharts.js. For more on each installation method, see the installation guide.