Vulnerability · Published May 12, 2026 · Assigned by GitHub_M
CVE-2026-44240basic-ftp allows a malicious FTP server to cause client-side denial of service via unbounded multiline control response buffering
High 7.5
In plain English
A high-severity uncontrolled resource consumption in basic-ftp from patrickjuchli. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | node-proxy-agents | no fix listed | DEBIAN-CVE-2026-44240 |
| Debian:14 | node-proxy-agents | 0~2025070717+~cs15.3.8-1 | DEBIAN-CVE-2026-44240 |
| Ubuntu:24.04:LTS | node-proxy-agents | no fix listed | UBUNTU-CVE-2026-44240 |
| Ubuntu:25.10 | node-proxy-agents | no fix listed | UBUNTU-CVE-2026-44240 |
| Ubuntu:26.04:LTS | node-proxy-agents | no fix listed | UBUNTU-CVE-2026-44240 |
| Ubuntu:26.10 | node-proxy-agents | no fix listed | UBUNTU-CVE-2026-44240 |
| npm | basic-ftp | 5.3.1 | GHSA-rpmf-866q-6p89 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| patrickjuchli | basic-ftp | < 5.3.1 |
Weakness: CWE-400, CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H