# CVE-2006-6171: Memory corruption in n/a

> ProFTPD FTP server suffers from a buffer underflow when CommandBufferSize is configured, potentially allowing remote attackers to cause denial of service or execute code.

- **Severity:** High 7.5 (`AV:N/AC:L/Au:N/C:P/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Nov 2006
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2006-6171, DSA-1218-1, GHSA-fg3g-4994-3829

## What is CVE-2006-6171?

CVE-2006-6171 is a high-severity memory corruption vulnerability in n/a, published on 30 Nov 2006. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ProFTPD 1.3.0a and earlier does not properly set the buffer size limit when CommandBufferSize is specified in the configuration file, which leads to an off-by-two buffer underflow.  NOTE: in November 2006, the role of CommandBufferSize was originally associated with CVE-2006-5815, but this was an error stemming from a vague initial disclosure.  NOTE: ProFTPD developers dispute this issue, saying that the relevant memory location is overwritten by assignment before further use within the affected function, so this is not a vulnerability

## Which versions are affected by CVE-2006-6171?

It affects 1 product.


Products: Proftpd Project Proftpd.

## How do I fix CVE-2006-6171?

Apply the vendor's patch.

## Is CVE-2006-6171 being exploited?

There is no known exploitation of CVE-2006-6171 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2006-5815](https://insights.sbomify.com/CVE-2006-5815/): Memory corruption in n/a (critical 10.0)
- [CVE-2003-0500](https://insights.sbomify.com/CVE-2003-0500/): SQL injection in n/a (critical 10.0)
- [CVE-1999-0911](https://insights.sbomify.com/CVE-1999-0911/): Memory corruption in n/a (critical 10.0)
- [CVE-2003-0831](https://insights.sbomify.com/CVE-2003-0831/): Memory corruption in n/a (critical 9.0)
- [CVE-2009-0542](https://insights.sbomify.com/CVE-2009-0542/): SQL injection in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2006-6171 and fix it if it is affected.

What it is: CVE-2006-6171 is a high-severity memory corruption vulnerability in n/a, published on 30 Nov 2006. 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-2006-6171 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-2006-6171/ (Markdown: https://insights.sbomify.com/CVE-2006-6171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2006-6171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2006-6171
- OSV: https://osv.dev/vulnerability/CVE-2006-6171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2006-6171/
Summaries are generated and may contain mistakes; the official description above is the record.