CVE-2026-118252

Highcharts JS is a JavaScript charting library based on SVG. From 1.0.0 until 4.2.3, Highcharts Dashboards edit mode parses fullscreen language labels as HTML rather than inserting them as text. An attacker who controls Dashboards language options can supply markup with event handlers, which execute in the hosting page origin when the fullscreen control is rendered. The label is reachable only when edit mode is enabled and viewFullscreen is present in the context-menu items. This issue is fixed in 4.2.3.

Highcharts Dashboards edit mode walks editableOptions propertyPath segments without rejecting prototype-related keys. An attacker controlling editableOptions can provide a path through __proto__ or constructor, and a user's edit writes the configured value onto Object.prototype, affecting JavaScript throughout the page. This is fixed in 4.2.2.

Highcharts Dashboards from 1.0.0 until 4.2.2 uses chartConstructor as an unchecked property lookup in the Highcharts namespace and invokes the selected member with the component container and chartOptions. An attacker who controls dashboard configuration can select a public utility function instead of a supported chart constructor, causing attacker-controlled options to be copied to the container as properties or attributes, and then markup and event handlers can execute in the hosting page origin when the board renders.

Highcharts Dashboards stores DataCursor listener and state maps in plain objects keyed by DataTable ID. A __proto__ table ID supplied through dataPool connector configuration resolves to Object.prototype, creating an enumerable property visible on every object that can throw and break features such as extremes synchronization. The issue affects versions 1.0.0 through 4.2.2 and is fixed in 4.2.2.