# CVE-2021-46686: Command injection in acmailer CGI

> Attackers can execute arbitrary OS commands via improper neutralization in acmailer CGI and DB products.

- **Severity:** Critical 9.8 (`CVSS:3.0/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:** 17 Feb 2025
- **Updated:** 18 Feb 2025
- **Also known as:** GHSA-5mr4-h7fw-j3h9

## What is CVE-2021-46686?

CVE-2021-46686 is a critical command injection vulnerability in Extra Innovation Inc. acmailer CGI, published on 17 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper neutralization of special elements used in an OS command ('OS Command Injection') issue exists in acmailer CGI ver.4.0.3 and earlier and acmailer DB ver.1.1.5 and earlier. If this vulnerability is exploited, an arbitrary OS command may be executed by an attacker.

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

## Which versions are affected by CVE-2021-46686?


## How do I fix CVE-2021-46686?

No fix has been published for CVE-2021-46686 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-46686 being exploited?

There is no known exploitation of CVE-2021-46686 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-46686 and fix it if it is affected.

What it is: CVE-2021-46686 is a critical command injection vulnerability in Extra Innovation Inc. acmailer CGI, published on 17 Feb 2025. 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-2021-46686 in the wild and no public exploit code.

Affected product: Extra Innovation Inc. acmailer CGI. 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-2021-46686/ (Markdown: https://insights.sbomify.com/CVE-2021-46686/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46686
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46686
- OSV: https://osv.dev/vulnerability/CVE-2021-46686

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-46686/
Summaries are generated and may contain mistakes; the official description above is the record.