# CVE-2021-3727: OS Command Injection in ohmyzsh/ohmyzsh

> Attackers can execute arbitrary commands via malicious quotes fetched by rand-quote and hitokoto plugins in Oh My Zsh.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 30 Nov 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-vg23-f593-6r27

## What is CVE-2021-3727?

CVE-2021-3727 is a high-severity command injection vulnerability in ohmyzsh/ohmyzsh, published on 30 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

# Vulnerability in `rand-quote` and `hitokoto` plugins **Description**: the `rand-quote` and `hitokoto` fetch quotes from quotationspage.com and hitokoto.cn respectively, do some process on them and then use `print -P` to print them. If these quotes contained the proper symbols, they could trigger command injection. Given that they're an external API, it's not possible to know if the quotes are safe to use. **Fixed in**: [72928432](https://github.com/ohmyzsh/ohmyzsh/commit/72928432). **Impacted areas**: - `rand-quote` plugin (`quote` function). - `hitokoto` plugin (`hitokoto` function).

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

## Which versions are affected by CVE-2021-3727?

It affects 1 product.


Products: Planetargon Oh My Zsh.

## How do I fix CVE-2021-3727?

No fix has been published for CVE-2021-3727 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3727 being exploited?

There is no known exploitation of CVE-2021-3727 in the wild and no public exploit code.

## Other vulnerabilities in ohmyzsh/ohmyzsh

- [CVE-2021-3934](https://insights.sbomify.com/CVE-2021-3934/): OS Command Injection in ohmyzsh/ohmyzsh (high 7.8)
- [CVE-2021-3725](https://insights.sbomify.com/CVE-2021-3725/): OS Command Injection in ohmyzsh/ohmyzsh (high 7.5)
- [CVE-2021-3726](https://insights.sbomify.com/CVE-2021-3726/): OS Command Injection in ohmyzsh/ohmyzsh (high 7.5)
- [CVE-2021-3769](https://insights.sbomify.com/CVE-2021-3769/): OS Command Injection in ohmyzsh/ohmyzsh (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3727 and fix it if it is affected.

What it is: CVE-2021-3727 is a high-severity command injection vulnerability in ohmyzsh/ohmyzsh, published on 30 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-3727 in the wild and no public exploit code.

Affected product: ohmyzsh/ohmyzsh. 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-2021-3727/ (Markdown: https://insights.sbomify.com/CVE-2021-3727/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3727
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3727
- OSV: https://osv.dev/vulnerability/CVE-2021-3727

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3727/
Summaries are generated and may contain mistakes; the official description above is the record.