# CVE-2026-78834: Code injection in n/a

> Authenticated low-privileged users can execute arbitrary code on the server via crafted content in the CoAuthors plugin for CMSimple.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Sep 2026
- **Updated:** 9 Sep 2026
- **Also known as:** GHSA-x6hj-fj57-58jm

## What is CVE-2026-78834?

CVE-2026-78834 is a high-severity code injection vulnerability in n/a, published on 8 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A code execution vulnerability exists in CMSimple 5.22 in the CoAuthors plugin. An authenticated low-privileged user who can modify page content and provide controlled imported content can trigger server-side execution by referencing crafted external or uploaded text content through the affected content import feature.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-78834?


## How do I fix CVE-2026-78834?

No fix has been published for CVE-2026-78834 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78834 being exploited?

There is no known exploitation of CVE-2026-78834 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78834 and fix it if it is affected.

What it is: CVE-2026-78834 is a high-severity code injection vulnerability in n/a, published on 8 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-78834 in the wild and no public exploit code.

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-2026-78834/ (Markdown: https://insights.sbomify.com/CVE-2026-78834/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78834
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78834
- OSV: https://osv.dev/vulnerability/CVE-2026-78834

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78834/
Summaries are generated and may contain mistakes; the official description above is the record.