VulnerabilityPublished 28 Oct 2026

CVE-2026-118247: Highcharts Dashboards / Grid Pro: `DataTable.setCell` and column writers treat `proto` as an

Affects @highcharts/dashboardsSource GCVE Database

Authoritative record:CVE-2026-118247· Medium 6.9

Not known to be exploited · CVSS 6.9 Medium : upgrade to 4.2.2 when convenient.

Data as of 28 Oct 2026, 21:14 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 4.2.2, 3.2.0

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: Active
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: High
Subsequent system confidentiality: Low
Subsequent system integrity: Low
Subsequent system availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: Active: Successful exploitation of this vulnerability requires a targeted user to perform specific, conscious interactions with the vulnerable system and the attacker’s payload, or the user’s interactions would actively subvert protection mechanisms which would lead to exploitation of the vulnerability.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: High: There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Subsequent System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Subsequent System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade @highcharts/dashboards to 4.2.2; @highcharts/grid-pro to 3.2.0.

Affected software

Product	Affected	Fixed in
npm@highcharts/dashboards	Affected >=1.0.0 <4.2.2	Fixed in 4.2.2
npm@highcharts/grid-pro	Affected >=2.0.0 <3.2.0	Fixed in 3.2.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Impact When a single cell value is written to a data table, the column id is used as a key on the table's column collection without filtering, so a column id of `__proto__` resolves to `Object.prototype`, is taken for an existing column, and the write lands at the row index on `Object.prototype`; a column id of `constructor` writes onto the `Object` constructor in the same way. In Dashboards releases that still supported column aliases, the id is first resolved through the alias map, so a literal `__proto__` id is redirected harmlessly there, while an alias whose target is `__proto__`, which the connector's data table options accept, reaches the same write. An attacker who controls the column id can thereby set integer-keyed properties on `Object.prototype`, one per row index, holding the written value; named properties cannot be reached through these paths, because the row index is a number. The integer keys still affect every object in the page: reading an out-of-range index on any array or plain object returns the injected value, and `for...in` over any object yields the injected keys, so unrelated code can take branches it should not using attacker-supplied data, and rendering can fail as a side effect. In Dashboards the write is reached through the Highcharts component's connector write-back, which is enabled by default through `allowConnectorUpdate` and takes the column id from the component's `columnAssignment`, or in the earliest releases from the series name, when a point is updated; in Grid Pro it is reached through cell editing in earlier releases and remains reachable through the public `DataTable` API. Exploitation requires that untrusted data reach the board or Grid configuration and that a point be updated or a cell edited, or that the application write a cell with an untrusted column id. Consequences beyond disruption depend on the consuming application. ### Workarounds Two measures are needed. The first closes the paths that reach `Object.prototype`; the second covers table construction, which cannot be patched from outside the library. #### 1. Strip unsafe keys from untrusted column data Apply this wherever column data enters your application, before it is handed to a grid, board or `DataTable`. This is the only measure that covers the `DataTable` constructor. ```js function stripUnsafeColumnIds(columns) { for (const key of ['__proto__', 'constructor']) { if (Object.prototype.hasOwnProperty.call(columns, key)) { delete columns[key]; } } return columns; } Grid.grid('container', { data: { columns: stripUnsafeColumnIds(untrustedColumns) } }); ``` #### 2. Patch the DataTable methods Needed if your application passes column ids that originate from untrusted input to `setCell`, `changeColumnId` or `setColumns`. Run it once at startup. ```js { const { DataTable } = Grid; // Or Dashboards if (!DataTable) { throw new Error('Patch loaded before Grid'); } const unsafe = (id) => id === '__proto__' || id === 'constructor'; const setCell = DataTable.prototype.setCell; DataTable.prototype.setCell = function (columnId, ...rest) { if (unsafe(columnId)) { return; } return setCell.call(this, columnId, ...rest); }; const changeColumnId = DataTable.prototype.changeColumnId; DataTable.prototype.changeColumnId = function (columnId, newColumnId) { if (unsafe(columnId) || unsafe(newColumnId)) { return false; } return changeColumnId.call(this, columnId, newColumnId); }; const setColumns = DataTable.prototype.setColumns; DataTable.prototype.setColumns = function (columns, ...rest) { const safe = {}; for (const key of Object.keys(columns || {})) { if (!unsafe(key)) { safe[key] = columns[key]; } } return setColumns.call(this, safe, ...rest); }; } ``` For npm, take `DataTable` from your import instead of the global — it is exported by Grid Lite, Grid Pro and Dashboards alike. ### 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/dashboards@4.2.2`. 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).

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (opens in a new tab)
Variant weakness
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.
Implementation
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
Architecture and Design
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
Implementation · Input Validation
When handling untrusted objects, validating using a schema can be used.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-1321

Technical details

References

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