CVE-2026-44240Public exploitNetwork attack vector

Client denial of service via unbounded response buffering

Published May 12, 2026 · Updated May 12, 2026

Resource exhaustion in basic-ftp before 5.3.1 allows remote attackers controlling an FTP server to hang or crash Node.js clients. FtpContext._onControlSocketData repeatedly reparses and retains an unterminated multiline banner in _partialResponse without a size limit. Exploitation occurs before FTP authentication when an application connects to an attacker-controlled or compromised endpoint, exhausting CPU and memory.

CVSS severity7.5
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in basic-ftp before 5.3.1 allows remote attackers controlling an FTP server to hang or crash Node.js clients. FtpContext._onControlSocketData repeatedly reparses and retains an unterminated multiline banner in _partialResponse without a size limit. Exploitation occurs before FTP authentication when an application connects to an attacker-controlled or compromised endpoint, exhausting CPU and memory.

The record

CVE
CVE-2026-44240
Published
May 12, 2026
Updated
May 12, 2026
Vendor
Patrick Juchli
Product
basic-ftp
Classifications
CWE-400, CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Patrick Juchli · basic-ftpversion=< 5.3.1

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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