CVE-2026-118246

Highcharts JS from 6.1.0 until 11.4.9, 12.6.1, and 3.1.0 follows dot-separated series.keys paths without filtering each segment. An attacker who controls series.keys and matching point data can use a path through __proto__ to assign arbitrary named properties to Object.prototype, visible to all JavaScript in the page, with no user interaction beyond rendering the chart.

Highcharts JS from 13.0.0 until 13.1.0 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, affecting reads and for-in enumeration across the page without user interaction beyond rendering the chart.

Highcharts JS from 12.0.0 until 12.6.1 and 13.1.0 falls back to assigning raw markup to innerHTML when DOMParser cannot return a document, before its allow-list is applied. In Chromium, the Trusted Types callback can throw while a beforeprint handler runs, so a page that redraws a chart during beforeprint can insert untrusted HTML text options into the hosting document, and event handlers in that markup run in the page origin when printing begins.