CVE-2020-1939Network attack vector

Unauthenticated service interruption via NULL pointer dereference

Published May 12, 2020 · Updated Aug 4, 2024

NULL pointer dereference in Apache NuttX Apps ftpd 6.15 through 8.2 allows remote attackers to interrupt the FTP service. Apache identifies ftpd as the affected component but has not published the handler, FTP command, or pointer operation that triggers the dereference. Exposure requires the optional Apps repository and ftpd to be enabled; the NuttX RTOS itself is not affected.

CVSS severity9.8
Critical
EPSS probability2.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Apache NuttX Apps ftpd 6.15 through 8.2 allows remote attackers to interrupt the FTP service. Apache identifies ftpd as the affected component but has not published the handler, FTP command, or pointer operation that triggers the dereference. Exposure requires the optional Apps repository and ftpd to be enabled; the NuttX RTOS itself is not affected.

The record

CVE
CVE-2020-1939
Published
May 12, 2020
Updated
Aug 4, 2024
Vendor
Apache Software Foundation
Product
Apache NuttX Apps ftpd FTP server
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=Apache NuttX (incubating) 6.15 to 8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apache Software Foundation · Apache NuttX Apps ftpd FTP serverversion=Apache NuttX (incubating) 6.15 to 8.2

Published CVSS scores

5.1NISTAV:N/AC:H/Au:N/C:P/I:P/A:P
9.8NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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