How severe is CVE-2020-1939?

CVE-2020-1939 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-1939 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-1939?

CVE-2020-1939 affects Apache Nuttx. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-1939?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-1939 published?

CVE-2020-1939 was published on 2020-05-12 and last updated on 2026-06-17.

CVE-2020-1939

CVE-2020-1939 is a critical-severity vulnerability in Apache Nuttx with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.1
EPSS exploit prediction: 2% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Apache Nuttx
Published: 2020-05-12
Last modified: 2026-06-17

Description

The Apache NuttX (Incubating) project provides an optional separate "apps" repository which contains various optional components and example programs. One of these, ftpd, had a NULL pointer dereference bug. The NuttX RTOS itself is not affected. Users of the optional apps repository are affected only if they have enabled ftpd. Versions 6.15 to 8.2 are affected.

Frequently asked questions

What is CVE-2020-1939?: The Apache NuttX (Incubating) project provides an optional separate "apps" repository which contains various optional components and example programs. One of these, ftpd, had a NULL pointer dereference bug. The NuttX RTOS itself is not affected. Users of the optional apps repository are affected only if they have enabled ftpd. Versions 6.15 to 8.2 are affected.
How severe is CVE-2020-1939?: CVE-2020-1939 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-1939 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-1939?: CVE-2020-1939 affects Apache Nuttx. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-1939?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-1939 published?: CVE-2020-1939 was published on 2020-05-12 and last updated on 2026-06-17.

References

https://lists.apache.org/thread.html/re3adc65ff4d8d9c34e5bccba3941a28cbb0a47191c150df2727e101d%40%3Cdev.nuttx.apache.org%3E

Affected products (1)

cpe:2.3:a:apache:nuttx:*:*:*:*:*:*:*:*

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Other CWE-476 (NULL Pointer Dereference) vulnerabilities

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CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
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