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...

Description

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.

Metrics

CVSS 4.0

9.3/10

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

EPSS Probability

0.74%

50.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-121

References

Timeline

Published: Aug 20, 2025
Last Modified: Jun 16, 2026
Status: Deferred

Frequently Asked Questions

What is 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 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.

How severe is CVE-2010-20049?

CVE-2010-20049 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 0.74% probability of exploitation in the next 30 days.

How do I fix CVE-2010-20049?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.