GHSA-gfvx-2c2g-38wq: Npm/highcharts vulnerability
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
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 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/highchartsto a version that resolves this vulnerability.Fixed in 13.1.0 - Upgrade
Upgrade
highchartsto a version that resolves this vulnerability.Fixed in 13.1.0 - Compensating control
Add the provided IIFE after Highcharts is loaded; it overrides optionsToObject and setNestedProperty to reject __proto__ and constructor keys.
Event History
Frequently Asked Questions
Which Highcharts versions are affected?
The affected version range is 6.1.0 through 13.0.2.
When is an application realistically exposed?
Exposure requires rendering series columns built from point objects whose keys an attacker can control. No additional user interaction is needed after the chart is rendered.
What does an attacker need to supply?
The attacker needs control of point objects containing keys such as __proto__ or constructor. Those keys can survive JSON.parse and cause integer-indexed properties to be written to Object.prototype.
What can be checked to determine whether a page has already been affected?
After rendering a potentially malicious chart, inspect Object.prototype for unexpected integer-keyed properties. Affected pages may also show attacker-controlled values when reading out-of-range indexes on arrays or plain objects, or unexpected keys during for...in iteration.
What can be done if upgrading is not immediately possible?
The advisory describes a drop-in IIFE workaround intended for all affected versions, to be run after Highcharts is loaded. Restricting untrusted point-object keys, especially __proto__ and constructor, also addresses the described attack prerequisite.