CVE-2026-44240 | basic-ftp allows a malicious FTP server to cause client-side denial of service via unbounded multiline control response buffering

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.

Published: 2026-05-12 Last update: 2026-05-14 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-44240 is rated Moderate Risk (43.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.46%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-44240

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.46% +0.44%
2 2026-05-22 0.08% 0.03% -0.05%
3 2026-05-13 — 0.08% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44240

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-44240

GitHub Security Advisory for CVE-2026-44240

GHSA-rpmf-866q-6p89 · Severity: high · Ecosystem: npm — basic-ftp allows a malicious FTP server to cause client-side denial of service via unbounded multiline control response buffering

OS Trackers for CVE-2026-44240

vendor priority summary link
debian not yet assigned CVE-2026-44240 not yet assigned priority: Debian including 1 source packages (node-proxy-agents), 3 status rows across 3 suites (forky, sid, trixie): resolved 2, open 1. https://security-tracker.debian.org/tracker/CVE-2026-44240
ubuntu medium CVE-2026-44240 medium priority: Ubuntu including 1 source packages (node-proxy-agents), 5 status rows across 5 suites (jammy, noble, questing, resolute, upstream): needs-triage 3, DNE 1, released 1. https://ubuntu.com/security/CVE-2026-44240

Affected software / configurations for CVE-2026-44240

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-44240

cvelogic Threat Intelligence