# CVE-2021-20850: Command injection in PowerCMS XMLRPC API

> Remote attackers can execute arbitrary OS commands via the PowerCMS XMLRPC API, requiring immediate upgrades to secure versions.

- **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:** 24 Nov 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-cw2g-2q23-x8ff

## What is CVE-2021-20850?

CVE-2021-20850 is a critical command injection vulnerability in Alfasado Inc. PowerCMS XMLRPC API, published on 24 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

PowerCMS XMLRPC API of PowerCMS 5.19 and earlier, PowerCMS 4.49 and earlier, PowerCMS 3.295 and earlier, and PowerCMS 2 Series (End-of-Life, EOL) allows a remote attacker to execute an arbitrary OS command via unspecified vectors.

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

## Which versions are affected by CVE-2021-20850?

It affects 1 product.


Products: Alfasado Powercms.

## How do I fix CVE-2021-20850?

No fix has been published for CVE-2021-20850 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20850 being exploited?

There is no known exploitation of CVE-2021-20850 in the wild and no public exploit code.

## Other vulnerabilities in Alfasado Inc. PowerCMS XMLRPC API

- [CVE-2022-33941](https://insights.sbomify.com/CVE-2022-33941/): Command injection in PowerCMS XMLRPC API (critical 9.8)
- [CVE-2025-46359](https://insights.sbomify.com/CVE-2025-46359/): Path traversal in PowerCMS (high 8.6)
- [CVE-2023-50297](https://insights.sbomify.com/CVE-2023-50297/): Open redirect in PowerCMS (PowerCMS 4 Series) (medium 6.1)
- [CVE-2019-6020](https://insights.sbomify.com/CVE-2019-6020/): Open redirect in PowerCMS (medium 6.1)
- [CVE-2023-49117](https://insights.sbomify.com/CVE-2023-49117/): Cross-site scripting in PowerCMS (PowerCMS 4 Series) (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20850 and fix it if it is affected.

What it is: CVE-2021-20850 is a critical command injection vulnerability in Alfasado Inc. PowerCMS XMLRPC API, published on 24 Nov 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-2021-20850 in the wild and no public exploit code.

Affected product: Alfasado Inc. PowerCMS XMLRPC API. 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-2021-20850/ (Markdown: https://insights.sbomify.com/CVE-2021-20850/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20850
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20850
- OSV: https://osv.dev/vulnerability/CVE-2021-20850

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20850/
Summaries are generated and may contain mistakes; the official description above is the record.