CVE-2024-8946: A vulnerability was found in MicroPython 1.23.0

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HIGH 7.3REMOTEDOWNGRADE

CVE-2024-8946 is a high-severity flaw (CVSS 7.3) affecting micropython. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-122, CWE-787
Published	2024-09-17
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: micropython

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

Am I affected?

Timeline

2024-09-17 19:15 UTCPublished CVE record published
2026-06-17 08:23 UTCUpdated Record last modified

micropython micropython DOWNGRADE

Affected: 1.23.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.23.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.23.0 (Debian / Ubuntu)

apt-cache madison micropython sudo apt install micropython=<VERSION_BEFORE_1.23.0> sudo apt-mark hold micropython

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list micropython sudo dnf downgrade micropython-<VERSION_BEFORE_1.23.0> sudo dnf versionlock add micropython

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-2024-8946?

micropython: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2024-8946 being exploited?

CVE-2024-8946 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-2024-8946 affect?

CVE-2024-8946 affects micropython. Severity is high (CVSS 7.3). A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow.

How urgent is CVE-2024-8946?

Priority 51/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-1998 LOW 3.3 UPGRADE A flaw has been found in micropython up to 1.27.0
CVE-2024-8948 HIGH 7.3 DOWNGRADE A vulnerability was found in MicroPython 1.23.0
CVE-2024-8947 MEDIUM 5.6 DOWNGRADE A vulnerability was found in MicroPython 1.22.2

References

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