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


- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** GHSA-c75x-9x9h-28rm

## What is CVE-2026-118247?

CVE-2026-118247 is a medium-severity vulnerability in @highcharts dashboards, published on 28 Oct 2026. 

### Official description

Highcharts JS is a JavaScript charting library based on SVG. From 1.0.0 until Dashboards 4.2.2, and from 2.0.0 until Grid Pro 3.2.0, Highcharts DataTable single-cell writers use an untrusted column ID as a key without rejecting __proto__ or constructor. DataTable.setCell, including Dashboards connector write-back and Grid Pro editing paths, can therefore write integer-indexed values onto Object.prototype or the Object constructor. In Dashboards releases with column aliases, a literal __proto__ ID is redirected by the alias map, while an alias targeting __proto__ reaches the unsafe write; later releases without aliases accept the unsafe ID directly. Those inherited values affect array and object reads and for-in enumeration throughout the page, which can alter application control flow or disrupt rendering. Exploitation requires control of the table or component column ID and a cell, point, or API write. This issue is fixed in Dashboards 4.2.2 and Grid Pro 3.2.0.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-118247?

4 open source packages ship an affected version, including @highcharts/dashboards and @highcharts/grid-pro.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@highcharts/dashboards` | npm | From 1.0.0 | 4.2.2 |
| `@highcharts/dashboards` | npm | From 1.0.0 | 4.2.2 |
| `@highcharts/grid-pro` | npm | From 2.0.0 | 3.2.0 |
| `@highcharts/grid-pro` | npm | From 2.0.0 | 3.2.0 |

## How do I fix CVE-2026-118247?

Upgrade @highcharts/dashboards to 4.2.2 or later.

## Is CVE-2026-118247 being exploited?

There is no known exploitation of CVE-2026-118247 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-118247 and fix it if it is affected.

What it is: CVE-2026-118247 is a medium-severity vulnerability in @highcharts dashboards, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-118247 in the wild and no public exploit code.

Affected packages and fixed versions:
- @highcharts/dashboards (npm): affected from 1.0.0; fixed in 4.2.2
- @highcharts/dashboards (npm): affected from 1.0.0; fixed in 4.2.2
- @highcharts/grid-pro (npm): affected from 2.0.0; fixed in 3.2.0
- @highcharts/grid-pro (npm): affected from 2.0.0; fixed in 3.2.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-118247/ (Markdown: https://insights.sbomify.com/CVE-2026-118247/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-118247
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-118247
- OSV: https://osv.dev/vulnerability/CVE-2026-118247

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-118247/
Summaries are generated and may contain mistakes; the official description above is the record.