Skip to content
Fencer Vulns
high 7.3

CVE-2024-8946 json

MicroPython VFS Unmount vfs.c mp_vfs_umount heap-based overflow

published 2024-09-17 2 y ago modified 2026-06-17 4 mo ago also GHSA-74qm-4v7r-jw2f , PYSEC-2024-91 , PYSEC-2024-93 , PYSEC-2024-95 , PYSEC-2024-96 , EUVD-2024-0102

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

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 to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Patch / fix

  • micropython Debian 14, Debian 13 1.24.0+ds-1

debian advisories DEBIAN-CVE-2024-8946

  • micropython Ubuntu Pro 20.04 LTS 1.12-1ubuntu0.1~esm1
  • micropython Ubuntu Pro 22.04 LTS 1.17+ds-1.1ubuntu2+esm1
  • micropython Ubuntu Pro 24.04 LTS 1.22.1+ds-1ubuntu0.24.04.1~esm1

ubuntu advisories UBUNTU-CVE-2024-8946

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-8946 updated cvss 7.3

micropython: heap buffer overflow via mp_vfs_umount

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/micropython/micropython/issues/13006 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/micropython/micropython/issues/13006#issuecomment-1820309455 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA 3.0 7.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
pypi micropython-copy
<=3.3.3.post3
all versions
 no fix listed
pypi micropython-io
<=0.1
all versions
 no fix listed
pypi micropython-os-path
<=0.1.3
all versions
 no fix listed
pypi micropython-string
<=0.1
all versions
 no fix listed

Affected products

  • n/a MicroPython
  • micropython micropython

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.