# CVE-2021-27104: Accellion FTA OS Command Injection

> Attackers can execute arbitrary OS commands via crafted POST requests to admin endpoints in Accellion FTA.

- **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:** Yes, since 3 Nov 2021 (CISA KEV), used in ransomware
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Feb 2021
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-54w2-m25f-gmqp

## What is CVE-2021-27104?

CVE-2021-27104 is a critical command injection vulnerability in n/a, published on 16 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Accellion FTA 9_12_370 and earlier is affected by OS command execution via a crafted POST request to various admin endpoints. The fixed version is FTA_9_12_380 and later.

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

## Which versions are affected by CVE-2021-27104?

It affects 1 product.


Products: Accellion Fta.

## How do I fix CVE-2021-27104?

No fix has been published for CVE-2021-27104 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Nov 2021.

## Is CVE-2021-27104 being exploited?

Yes. Attackers have exploited CVE-2021-27104 in the wild since at least 3 Nov 2021, including in ransomware campaigns.

## Other vulnerabilities in n/a

- [CVE-2021-27101](https://insights.sbomify.com/CVE-2021-27101/): Accellion FTA SQL Injection (critical 9.8, exploited in the wild)
- [CVE-2021-27103](https://insights.sbomify.com/CVE-2021-27103/): Accellion FTA Server-Side Request Forgery (SSRF) (critical 9.8, exploited in the wild)
- [CVE-2021-27102](https://insights.sbomify.com/CVE-2021-27102/): Accellion FTA OS Command Injection (high 7.8, exploited in the wild)
- [CVE-2021-27730](https://insights.sbomify.com/CVE-2021-27730/): Command injection in n/a (critical 9.8)
- [CVE-2021-27731](https://insights.sbomify.com/CVE-2021-27731/): Cross-site scripting in n/a (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27104 and fix it if it is affected.

What it is: CVE-2021-27104 is a critical command injection vulnerability in n/a, published on 16 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-27104 in the wild since at least 3 Nov 2021, including in ransomware campaigns.

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-2021-27104/ (Markdown: https://insights.sbomify.com/CVE-2021-27104/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27104
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27104
- OSV: https://osv.dev/vulnerability/CVE-2021-27104

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27104/
Summaries are generated and may contain mistakes; the official description above is the record.