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Fencer Intel
critical 9.3

CVE-2010-20049 json

LeapFTP < 3.1.x Stack Buffer Overflow

published last yr. modified 4mo ago also EUVD-2010-5303

cvss
9.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
1
Metasploit

Summary

LeapFTP < 3.1.x contains a stack-based buffer overflow vulnerability in its FTP client parser. When the client receives a directory listing containing a filename longer than 528 bytes, the application fails to properly bound-check the input and overwrites the Structured Exception Handler (SEH) chain. This allows an attacker operating a malicious FTP server to execute arbitrary code on the victim’s machine when the file is listed or downloaded.

Patch / fix

Is CVE-2010-20049 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Timeline

  1. First public exploit (Metasploit exploit/windows/ftp/leapftp_list_reply)
  2. Published

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
last yr.

Exploit prediction

1.19% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • Metasploit exploit/windows/ftp/leapftp_list_reply LeapFTP 3.0.1 Stack Buffer Overflow metasploit exploit, good rank, 2010-10-12
  • raw.githubusercontent.com https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/windows/ftp/leapftp_list_reply.rb referenced PoC, tagged "exploit" by a source, unverified
  • exploit-db.com https://www.exploit-db.com/exploits/16704 referenced PoC, tagged "exploit" by a source, unverified
  • web.archive.org https://web.archive.org/web/20111016194057/https://www.corelan.be/index.php/2010/10/12/death-of-an-ftp-client/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 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
CNA 4.0 9.3 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • LeapWare LeapFTP

Classification

Weakness
  • CWE-121 Stack-based Buffer Overflow

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.