Highcharts up to 4.2.1 Dashboards prototype pollution

Summaryinfo

A vulnerability, which was classified as critical, was found in Highcharts up to 4.2.1. Impacted is an unknown function of the component Dashboards. The manipulation results in prototype pollution. This vulnerability is identified as CVE-2026-118243. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Highcharts up to 4.2.1. It has been classified as critical. Affected is some unknown functionality of the component Dashboards. The manipulation with an unknown input leads to a prototype pollution vulnerability. CWE is classifying the issue as CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Highcharts JS is a JavaScript charting library based on SVG. From 1.0.0 until 4.2.2, 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, and sync registration creates an enumerable property there whose suffix can be influenced through the sync group option. The property is visible on every object, and lasting sync states can throw and stop features such as extremes synchronization. Exploitation requires untrusted dashboard configuration and an enabled component sync, but no user interaction beyond loading the board. This issue is fixed in 4.2.2.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-118243 since 10/27/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 4.2.2 eliminates this vulnerability.

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Productinfo

Name

• Highcharts

Version

• 4.2.0
• 4.2.1

Website

• Product: https://github.com/highcharts/highcharts/

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