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High, CVSS 7.5amended

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

CVE-2026-44240GHSA-rpmf-866q-6p89

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (basic-ftp 5.3.1), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-44240: 0.51% estimated exploitation activity in the next 30 days; percentile 43.82 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary 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. --- Details Root cause The root cause is that incomplete FTP multiline control responses are buffered without an upper bound. FtpContext stores incomplete control-channel data in partialResponse:…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-rpmf-866q-6p89

  2. Revision 1 · created ·

    Published from osv record GHSA-rpmf-866q-6p89

Agent brief

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# Patch Next advisory brief: CVE-2026-44240

Advisory: basic-ftp allows a malicious FTP server to cause client-side denial of service via unbounded multiline control response buffering
IDs: CVE-2026-44240, GHSA-rpmf-866q-6p89
Record: https://patchnext.com/advisories/cve-2026-44240 (revision 2, source checked 26 Oct 2026, 12:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: basic-ftp 5.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm basic-ftp: affected <= 5.3.0; fixed in 5.3.1

## Suggested inspection (read-only)
- `npm ls basic-ftp --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on basic-ftp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-rpmf-866q-6p89 (OSV record GHSA-rpmf-866q-6p89 lists affected ranges: npm basic-ftp >=0 <5.3.1 (fixed))
- Verified: https://github.com/advisories/GHSA-rpmf-866q-6p89 (GitHub-reviewed advisory GHSA-rpmf-866q-6p89 lists affected ranges: npm basic-ftp >=0 <=5.3.0)

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