CVE-2026-118243

Highcharts Dashboards: `__proto__` data table id writes sync listeners to `Object.prototype`

MEDIUM
5.3
CVSS Score
Published: October 28, 2026 at 05:33 PM UTC
Updated: October 29, 2026 at 03:08 PM UTC
1 product affected across 1 vendorHighcharts

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.0.0 ≤ v < 4.2.21.0.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

5.3MEDIUMGitHub_M
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-1321

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