CVE-2020-24863: A memory corruption vulnerability was found in the kernel function kern_getfsstat in MidnightBSD before 1.2.7

Q: How do I fix CVE-2020-24863?

midnightbsd: upgrade to 1.2.7; freebsd: upgrade to newer than 11.4. Exact commands for each OS are on this page.

Q: Is CVE-2020-24863 being exploited?

CVE-2020-24863 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-24863 affect?

CVE-2020-24863 affects midnightbsd, freebsd. Severity is medium (CVSS 5.5). A memory corruption vulnerability was found in the kernel function kern_getfsstat in MidnightBSD before 1.2.7 and 1.3 through 2020-08-19, and FreeBSD through 11.4, that allows an attacker to trigger an invalid free and crash the system via

Q: How urgent is CVE-2020-24863?

Priority 36/100. Public exploit reference

Routine

MEDIUM 5.5UPGRADEUPGRADE

CVE-2020-24863 is a medium-severity flaw (CVSS 5.5) affecting midnightbsd, freebsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A memory corruption vulnerability was found in the kernel function kern_getfsstat in MidnightBSD before 1.2.7 and 1.3 through 2020-08-19, and FreeBSD through 11.4, that allows an attacker to trigger an invalid free and crash the system via a crafted size value in conjunction with an invalid mode.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-787
Published	2020-09-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: freebsd · midnightbsd

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

Am I affected?

Timeline

2020-09-03 15:15 UTCPublished CVE record published
2026-06-17 03:06 UTCUpdated Record last modified

midnightbsd midnightbsd UPGRADE

Affected: < 1.2.7 · >= 1.3 and <= 2020-08-19

Fixed in: 1.2.7

Safe to downgrade to: a release before 1.3

1. Check installed version

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

2. UPGRADE to 1.2.7 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade midnightbsd

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 1.3 (Debian / Ubuntu)

apt-cache madison midnightbsd sudo apt install midnightbsd=<VERSION_BEFORE_1.3> sudo apt-mark hold midnightbsd

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

dnf --showduplicates list midnightbsd sudo dnf downgrade midnightbsd-<VERSION_BEFORE_1.3> sudo dnf versionlock add midnightbsd

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.

freebsd freebsd UPGRADE

Affected: <= 11.4

Fixed in: newer than 11.4

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2020-24863?

midnightbsd: upgrade to 1.2.7; freebsd: upgrade to newer than 11.4. Exact commands for each OS are on this page.

Is CVE-2020-24863 being exploited?

CVE-2020-24863 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-2020-24863 affect?

CVE-2020-24863 affects midnightbsd, freebsd. Severity is medium (CVSS 5.5). A memory corruption vulnerability was found in the kernel function kern_getfsstat in MidnightBSD before 1.2.7 and 1.3 through 2020-08-19, and FreeBSD through 11.4, that allows an attacker to trigger an invalid free and crash the system via

How urgent is CVE-2020-24863?

Priority 36/100. Public exploit reference

Related CVEs

CVE-2020-24385 MEDIUM 5.5 UPGRADE UPGRADE In MidnightBSD before 1.2.6 and 1.3 before August 2020, and FreeBSD before 7, a NULL pointer dereference was f

References

← Back to latest CVEs