# CVE-2021-43936: Distributed Data Systems WebHM

> Attackers can upload dangerous files to the WebHMI portal, potentially leading to arbitrary code execution within the product environment.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:** 6 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-9558-55mx-wf4p

## What is CVE-2021-43936?

CVE-2021-43936 is a critical vulnerability in Distributed Data Systems WebHMI, published on 6 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The software allows the attacker to upload or transfer files of dangerous types to the WebHMI portal, that may be automatically processed within the product's environment or lead to arbitrary code execution.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2021-43936?

It affects 1 product.


Products: Webhmi Webhmi Firmware.

## How do I fix CVE-2021-43936?

No fix has been published for CVE-2021-43936 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43936 being exploited?

There is no known exploitation of CVE-2021-43936 in the wild and no public exploit code.

Public exploit code:

- CVE-2021-43936 is a critical vulnerability (CVSS3 10.0) leading to Remote Code Execution (RCE) in WebHMI Firmware. (github_poc): https://github.com/LongWayHomie/CVE-2021-43936
- WebHMI 4.0 - Remote Code Execution (RCE) (Authenticated) (exploitdb)

## Other vulnerabilities in Distributed Data Systems WebHMI

- [CVE-2021-43931](https://insights.sbomify.com/CVE-2021-43931/): Distributed Data Systems WebHM (critical 9.8)
- [CVE-2022-2253](https://insights.sbomify.com/CVE-2022-2253/): Distributed Data Systems WebHMI OS Command Injection (critical 9.1)
- [CVE-2022-2254](https://insights.sbomify.com/CVE-2022-2254/): Distributed Data Systems WebHMI Cross-site Scripting (medium 6.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43936 and fix it if it is affected.

What it is: CVE-2021-43936 is a critical vulnerability in Distributed Data Systems WebHMI, published on 6 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-43936 in the wild and no public exploit code.

Affected product: Distributed Data Systems WebHMI. 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-2021-43936/ (Markdown: https://insights.sbomify.com/CVE-2021-43936/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43936
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43936
- OSV: https://osv.dev/vulnerability/CVE-2021-43936

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43936/
Summaries are generated and may contain mistakes; the official description above is the record.