CVE-2020-1939: The Apache NuttX (Incubating) project provides an optional separate "apps" repository which contains various o

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CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2020-1939 is a critical-severity flaw (CVSS 9.8) affecting nuttx. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.6% (top 15%)
CISA exploited list	No
Weakness	CWE-476
Published	2020-05-12
Last modified	2026-06-17

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-05-12 15:15 UTCPublished CVE record published
2026-06-17 03:02 UTCUpdated Record last modified

apache nuttx UPGRADE

Affected: >= 6.15 and <= 8.2

Fixed in: newer than 8.2

Safe to downgrade to: a release before 6.15

1. Check installed version

apt-cache policy nuttx || rpm -q nuttx || nuttx --version

2. UPGRADE to newer than 8.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nuttx

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nuttx

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 6.15 (Debian / Ubuntu)

apt-cache madison nuttx sudo apt install nuttx=<VERSION_BEFORE_6.15> sudo apt-mark hold nuttx

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list nuttx sudo dnf downgrade nuttx-<VERSION_BEFORE_6.15> sudo dnf versionlock add nuttx

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-1939?

nuttx: upgrade to newer than 8.2. Exact commands for each OS are on this page.

Is CVE-2020-1939 being exploited?

CVE-2020-1939 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-1939 affect?

CVE-2020-1939 affects nuttx. Severity is critical (CVSS 9.8). 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 affe

How urgent is CVE-2020-1939?

Priority 66/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2025-48769 HIGH 8.1 UPGRADE Use After Free vulnerability was discovered in fs/vfs/fs_rename code of the Apache NuttX RTOS, that due recurs
CVE-2025-48768 MEDIUM 6.5 UPGRADE Release of Invalid Pointer or Reference vulnerability was discovered in fs/inode/fs_inoderemove code of the Ap
CVE-2025-47869 CRITICAL 9.8 UPGRADE Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability was discovered in Apache
CVE-2025-47868 CRITICAL 9.8 UPGRADE Out-of-bounds Write resulting in possible Heap-based Buffer Overflow vulnerability was discovered in tools/bdf
CVE-2025-35003 CRITICAL 9.8 UPGRADE Improper Restriction of Operations within the Bounds of a Memory Buffer and Stack-based Buffer Overflow vulner

References

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