# CVE-2026-4591: kalcaddle kodbox fileThumb Endpoint app.php checkBin os command injection

> Remote attackers can execute arbitrary OS commands via the fileThumb endpoint in kodbox, leading to potential system compromise.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Mar 2026
- **Updated:** 23 Mar 2026
- **Also known as:** GHSA-rjfv-p85j-26xf

## What is CVE-2026-4591?

CVE-2026-4591 is a medium-severity command injection vulnerability in kalcaddle kodbox, published on 23 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A weakness has been identified in kalcaddle kodbox 1.64. This affects the function checkBin of the file /workspace/source-code/plugins/fileThumb/app.php of the component fileThumb Endpoint. Executing a manipulation can lead to os command injection. The attack can be executed remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-77 (Improper Neutralization of Special Elements used in a Command)

## Which versions are affected by CVE-2026-4591?


## How do I fix CVE-2026-4591?

No fix has been published for CVE-2026-4591 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4591 being exploited?

There is no known exploitation of CVE-2026-4591 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4591 and fix it if it is affected.

What it is: CVE-2026-4591 is a medium-severity command injection vulnerability in kalcaddle kodbox, published on 23 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-4591 in the wild and no public exploit code.

Affected product: kalcaddle kodbox. 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-2026-4591/ (Markdown: https://insights.sbomify.com/CVE-2026-4591/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4591
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4591
- OSV: https://osv.dev/vulnerability/CVE-2026-4591

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4591/
Summaries are generated and may contain mistakes; the official description above is the record.