patrickjuchli basic-ftp up to 5.1.x downloadToDir path traversal

Summaryinfo

A vulnerability was found in patrickjuchli basic-ftp up to 5.1.x. It has been classified as critical. This vulnerability affects the function downloadToDir. This manipulation causes path traversal. The identification of this vulnerability is CVE-2026-27699. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in patrickjuchli basic-ftp up to 5.1.x. Affected by this vulnerability is the function downloadToDir. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

The `basic-ftp` FTP client library for Node.js contains a path traversal vulnerability (CWE-22) in versions prior to 5.2.0 in the `downloadToDir()` method. A malicious FTP server can send directory listings with filenames containing path traversal sequences (`../`) that cause files to be written outside the intended download directory. Version 5.2.0 patches the issue.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-27699 since 02/23/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 300394 (Linux Distros Unpatched Vulnerability : CVE-2026-27699), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.2.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (300394). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• patrickjuchli

Name

• basic-ftp

Version

• 5.0
• 5.1

Website

• Product: https://github.com/patrickjuchli/basic-ftp/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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