# CVE-2010-4221: Memory corruption in n/a

> Remote attackers can execute arbitrary code on ProFTPD servers via stack-based buffer overflows triggered by TELNET IAC escape characters.

- **Severity:** Critical 10.0 (`AV:N/AC:L/Au:N/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Nov 2010
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2010-4221, GHSA-gf2w-q84f-pmmw

## What is CVE-2010-4221?

CVE-2010-4221 is a critical memory corruption vulnerability in n/a, published on 9 Nov 2010. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Multiple stack-based buffer overflows in the pr_netio_telnet_gets function in netio.c in ProFTPD before 1.3.3c allow remote attackers to execute arbitrary code via vectors involving a TELNET IAC escape character to a (1) FTP or (2) FTPS server.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2010-4221?

It affects 1 product.


Products: Proftpd Proftpd.

## How do I fix CVE-2010-4221?

Upgrade to a fixed version.

## Is CVE-2010-4221 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2010-4221 exists.

Public exploit code:

- This exploit was written to study some concepts, enjoy! (github_poc): https://github.com/M41doror/cve-2010-4221
- ProFTPD 1.3.2rc3 - 1.3.3b Telnet IAC Buffer Overflow (FreeBSD) (metasploit)
- ProFTPD 1.3.2rc3 - 1.3.3b Telnet IAC Buffer Overflow (Linux) (metasploit)
- ProFTPd IAC 1.3.x - Remote Command Execution (exploitdb)
- ProFTPd 1.3.2 rc3 < 1.3.3b (FreeBSD) - Telnet IAC Buffer Overflow (Metasploit) (exploitdb)
- ProFTPd 1.3.2 rc3 < 1.3.3b (Linux) - Telnet IAC Buffer Overflow (Metasploit) (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2010-20103](https://insights.sbomify.com/CVE-2010-20103/): ProFTPD 1.3.3c Backdoor Command Execution (critical 9.3)
- [CVE-2011-4130](https://insights.sbomify.com/CVE-2011-4130/): Use after free in n/a (critical 9.0)
- [CVE-2026-63090](https://insights.sbomify.com/CVE-2026-63090/): ProFTPD mod_sftp Heap Buffer Overflow via SFTP Packet Reassembly (high 8.7)
- [CVE-2026-35025](https://insights.sbomify.com/CVE-2026-35025/): ProFTPD ACL Bypass via /proc/self/root Path Prefix in RNFR (high 8.6)
- [CVE-2026-42167](https://insights.sbomify.com/CVE-2026-42167/): SQL injection in ProFTPD (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2010-4221 and fix it if it is affected.

What it is: CVE-2010-4221 is a critical memory corruption vulnerability in n/a, published on 9 Nov 2010. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2010-4221 exists.

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-2010-4221/ (Markdown: https://insights.sbomify.com/CVE-2010-4221/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2010-4221
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2010-4221
- OSV: https://osv.dev/vulnerability/CVE-2010-4221

---
From sbomify Insights: https://insights.sbomify.com/CVE-2010-4221/
Summaries are generated and may contain mistakes; the official description above is the record.