# CVE-2026-78847: Code injection in n/a

> Attackers can execute arbitrary code via JavaScript injection in front matter parsing due to unsafe eval usage in the gray-matter library.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Sep 2026
- **Updated:** 22 Sep 2026
- **Also known as:** GHSA-j9gx-vjm3-jpmm

## What is CVE-2026-78847?

CVE-2026-78847 is a critical code injection vulnerability in n/a, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue in gray-matter All versions (verified on 4.0.3) allows the JavaScript engine in lib/engines.js using eval() to parse front matter when language is js/javascript.This allows arbitrary code execution.

Weakness: CWE-95 (Improper Neutralization of Directives in Dynamically Evaluated Code)

## Which versions are affected by CVE-2026-78847?


## How do I fix CVE-2026-78847?

No fix has been published for CVE-2026-78847 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78847 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-78847 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78847 and fix it if it is affected.

What it is: CVE-2026-78847 is a critical code injection vulnerability in n/a, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-78847 exists.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-78847/ (Markdown: https://insights.sbomify.com/CVE-2026-78847/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78847
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78847
- OSV: https://osv.dev/vulnerability/CVE-2026-78847

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78847/
Summaries are generated and may contain mistakes; the official description above is the record.