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Fencer Vulns
medium 5.6

CVE-2024-8947 json

MicroPython objarray.c use after free

published 2024-09-17 2 y ago modified 2026-06-17 4 mo ago also GHSA-pwwp-3q7j-9mx8 , PYSEC-2024-92 , PYSEC-2024-94 , EUVD-2024-0103

cvss
5.6
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 1.22.2. It has been declared as critical. Affected by this vulnerability is an unknown functionality of the file py/objarray.c. The manipulation leads to use after free. The attack can be launched remotely. The complexity of an attack is rather high. The exploitation appears to be difficult. Upgrading to version 1.23.0 is able to address this issue. The identifier of the patch is 4bed614e707c0644c06e117f848fa12605c711cd. It is recommended to upgrade the affected component. In micropython objarray component, when a bytes object is resized and copied into itself, it may reference memory that has already been freed.

Patch / fix

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

debian advisories DEBIAN-CVE-2024-8947

  • 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-2024-8947

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

  • micropython openSUSE Tumbleweed 1.28.0-2.1

opensuse advisories openSUSE-SU-2026:10704-1

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-2024-8947 updated cvss 8.1

micropython: use after free vulnerability

  • 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

1.02% 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/13283 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/micropython/micropython/issues/13283#issuecomment-1918479709 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
CNA 3.1 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA 3.0 5.6 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA 2.0 5.1 AV:N/AC:H/Au:N/C:P/I:P/A:P
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:H/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 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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

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.