CVE-2010-20049

published 2025-08-20

CVE-2010-20049: 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…

Priority P2 64 critical 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

EXPLOIT

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.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
leapware	leapftp	< 3.1.*	3.1.*

Detection & IOCs extracted from sources · hover to see the quote

version LeapFTP 3.0.1↗

• → Detect FTP directory listing responses containing filenames exceeding 528 bytes in length, which is the overflow threshold for LeapFTP's parser. ↗
• → Flag FTP LIST/NLST responses from untrusted servers where any single filename token exceeds 528 bytes; this is the specific trigger condition for the stack-based buffer overflow. ↗
• → The Metasploit module targets the LeapFTP 3.0.1 client via the windows/ftp/leapftp_list_reply exploit path; alert on process crashes or shellcode execution originating from the LeapFTP process after receiving a LIST reply. ↗

• · Vulnerability affects LeapFTP versions prior to 3.1.x; version 3.0.1 is explicitly confirmed vulnerable. Ensure version scope is validated before deploying detections to avoid false positives on patched versions. ↗

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