CVE-2026-44240: Patrickjuchli Basic-FTP

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

basic-ftp is an FTP client for Node.js. Prior to 5.3.1, basic-ftp is vulnerable to client-side denial of service when parsing FTP control-channel multiline responses. A malicious or compromised FTP server can send an unterminated multiline response during the initial FTP banner phase, before authentication. The client keeps appending attacker-controlled data into FtpContext._partialResponse and repeatedly reparses the accumulated buffer without enforcing a maximum control response size. As a result, an application using basic-ftp can remain stuck in connect() while memory and CPU usage grow under attacker-controlled input. This can lead to process-level denial of service, container OOM kills, worker restarts, queue backlog, or service degradation in applications that automatically connect to FTP endpoints. This vulnerability is fixed in 5.3.1.

Affected products

• Patrickjuchli Basic-FTP: before 5.3.1 (fixed in 5.3.1)

Published 2026-05-12. Last modified 2026-06-17.