Security readout for executives and security teams
Plain-English summary
This is a critical memory-corruption flaw in the legacy LeapFTP client. A malicious FTP server can send an overlong filename in a directory listing and potentially run code on the client machine. The sources show public exploit material, but they do not show confirmed active exploitation or CISA KEV listing.
Executive priority
Treat this as urgent for environments with legacy FTP workflows. The risk is high because successful exploitation can execute code on user endpoints, but priority should be based on whether LeapFTP is actually present. If absent, document non-exposure and monitor for reintroduction.
Technical view
LeapFTP before 3.1.x has a stack-based buffer overflow in FTP directory listing parsing. A filename longer than 528 bytes can overwrite the SEH chain, enabling arbitrary code execution in the client process. The CVE maps to CWE-121 and carries CVSS 4.0 score 9.3.
Likely exposure
Exposure is mainly legacy Windows endpoints where LeapFTP older than 3.1.x remains installed and connects to untrusted or compromised FTP servers. Modern environments are unlikely exposed unless this old client persists in operational workflows, unmanaged workstations, or archived build and transfer processes.
Exploitation context
The source bundle includes public exploit references and a technical write-up. That supports exploit availability, not confirmed active exploitation. CISA KEV is false in the provided data. Exploitation depends on the vulnerable client processing a crafted FTP listing from a malicious server.
Researcher notes
Evidence is consistent across the CVE description, VulnCheck advisory, exploit references, and archived technical write-up. The affected-product metadata in the bundle is sparse, so version conclusions should be validated against endpoint inventory and vendor guidance rather than inferred from CPE data.
Mitigation direction
- Inventory endpoints for LeapFTP and remove unsupported installations.
- Upgrade LeapFTP using vendor guidance if a supported fixed version is available.
- Retire versions older than 3.1.x where upgrade assurance is unclear.
- Restrict legacy FTP client use to trusted servers only.
- Monitor EDR for suspicious LeapFTP crashes or process behavior.
Validation and detection
- Search software inventory for LeapFTP installations and versions.
- Confirm whether any detected installations are older than 3.1.x.
- Review proxy, firewall, and EDR logs for LeapFTP network activity.
- Check vulnerability tooling coverage for CVE-2010-20049.
- Document any business process still requiring LeapFTP.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-121: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2010-20049 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.3 (4.0)
- Known Exploited
- No
- Published
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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: 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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/windows/ftp/leapftp_list_reply.rbCVE reference, VulnCheck · exploit
- https://www.exploit-db.com/exploits/16704CVE reference, VulnCheck · exploit
- https://web.archive.org/web/20111016194057/https://www.corelan.be/index.php/2010/10/12/death-of-an-ftp-client/CVE reference, VulnCheck · technical-description, exploit
- https://web.archive.org/web/20111013232627/http://www.leapware.com/CVE reference, VulnCheck · vendor-advisory, patch
- https://www.vulncheck.com/advisories/leapftp-stack-buffer-overflowCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.