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

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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.

Source published

28 Oct 2026 17:33:31 UTC

Source modified

2 Nov 2026 20:26:32 UTC

Observed here

2 Nov 2026 21:57:16 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:L/SI:L/SA:L

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.

Source published

Oct 28, 2026, 5:33:31 PM (timezone not stated)

Source modified

Nov 2, 2026, 8:26:32 PM (timezone not stated)

Observed here

6 Nov 2026 00:43:22 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:L/SI:L/SA:L

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.

Source published

28 Oct 2026 18:17:15 UTC

Source modified

2 Nov 2026 21:17:26 UTC

Observed here

5 Nov 2026 23:38:43 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

### Impact The data cursor keeps its listener and state bookkeeping in plain objects keyed by data table id, so a table id of `__proto__` supplied in the `dataPool` connector configuration resolves to `Object.prototype` when a sync registers its listeners, and the registration creates a property on `Object.prototype` named after the sync state and holding the internal listener array. The property name begins with a state prefix fixed by the library, to which the sync `group` option can append an attacker-chosen suffix, and its value is the library's own listener array, but the property is enumerable and visible on every object in the page, and emitting a lasting state for that table id then throws, so syncs that keep lasting states, such as `extremes`, stop working. Exploitation requires that untrusted data reach the Dashboards configuration and that a sync such as `highlight` or `extremes` be enabled on a component using that table, which the same configuration can do. No user interaction is required beyond loading the board. The injected property is inert until other code on the page reads or enumerates it, so consequences depend on the consuming application. ### Workarounds **Drop-in fix - for any Highcharts Dashboards versions affected (1.0.0-4.2.1).** Add the below IIFE to run after Highcharts Dashboards is loaded. ``` !function(t){if(t&&t.DataCursor&&t.DataTable){var e=t.DataCursor.prototype,r=t.DataTable.prototype;e.tableIdPollutionPatched||(e.tableIdPollutionPatched=!0,null!==Object.getPrototypeOf((new t.DataCursor).listenerMap)&&['addListener','emitCursor','remitCursor','removeListener'].forEach(function(t){var r=e[t];r&&(e[t]=function(){var t;return t=this,['listenerMap','stateMap'].forEach(function(e){var r,a=t[e];a&&null!==Object.getPrototypeOf(a)&&(r=Object.create(null),Object.keys(a).forEach(function(t){r[t]=a[t]}),t[e]=r)}),r.apply(this,arguments)})}),'__proto__'!==new t.DataTable({id:'__proto__'}).id||Object.getOwnPropertyDescriptor(r,'id')||Object.defineProperty(r,'id',{configurable:!0,enumerable:!0,get:function(){return this.safeTableId},set:function(e){'__proto__'!==e&&'constructor'!==e||(e=t.uniqueKey(),this.autoId=!0),this.safeTableId=e}}))}}(Dashboards); ``` [Live demo & testing](https://jsfiddle.net/BlackLabel/jwqazb51/) ### 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/[email protected]`. If you load Highcharts Dashboards from a CDN, use a versioned URL, for example `https://code.highcharts.com/dashboards/4.2.2/dashboards.js`. For more on each installation method, see the [installation guide](https://www.highcharts.com/docs/dashboards/installation).

Source published

28 Oct 2026 19:55:32 UTC

Source modified

28 Oct 2026 20:15:06 UTC

Observed here

28 Oct 2026 20:55:42 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:L/SI:L/SA:L

Publisher rating · MODERATE