# CVE-2011-0721: Other in n/a

> Local attackers can inject CRLF characters into GECOS fields to modify /etc/passwd, potentially adding unauthorized users or groups.

- **Severity:** Medium 6.4 (`AV:N/AC:L/Au:N/C:N/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Feb 2011
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2011-0721, DSA-2164-1, GHSA-6wqp-749m-jfw7

## What is CVE-2011-0721?

CVE-2011-0721 is a medium-severity vulnerability in n/a, published on 18 Feb 2011. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Multiple CRLF injection vulnerabilities in (1) chfn and (2) chsh in shadow 1:4.1.4 allow local users to add new users or groups to /etc/passwd via the GECOS field.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2011-0721?

It affects 1 product.


Products: Debian Shadow.

## How do I fix CVE-2011-0721?

Apply the vendor's patch.

## Is CVE-2011-0721 being exploited?

There is no known exploitation of CVE-2011-0721 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2008-5394](https://insights.sbomify.com/CVE-2008-5394/): Path traversal in n/a (high 7.2)
- [CVE-2004-1001](https://insights.sbomify.com/CVE-2004-1001/): Security feature bypass in n/a (medium 4.6)
- [CVE-2006-1174](https://insights.sbomify.com/CVE-2006-1174/): Misconfiguration in n/a (low 3.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-0721 and fix it if it is affected.

What it is: CVE-2011-0721 is a medium-severity vulnerability in n/a, published on 18 Feb 2011. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2011-0721 in the wild and no public exploit code.

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-2011-0721/ (Markdown: https://insights.sbomify.com/CVE-2011-0721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-0721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-0721
- OSV: https://osv.dev/vulnerability/CVE-2011-0721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-0721/
Summaries are generated and may contain mistakes; the official description above is the record.