NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
🐍 PyPI
Not in CISA KEV

CVE-2024-8948 — micropython-copy

Fix: micropython/micropython@908ab1c

CVE-2024-8948 is a CWE-122 vulnerability in micropython-copy. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

MicroPython objint.c mpz_as_bytes heap-based overflow

Also known asGHSA-vh3x-525m-jp4rPYSEC-2024-87PYSEC-2024-88PYSEC-2024-89
Published
Updated
Affected
3 pkgs
Patched
See advisory
Exploits
1 known
Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-8948.

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk
0.00%0.50%1.00%1.49%0.1%1.0%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected
🐍micropython-copy🐍micropython-io🐍micropython-os

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

A vulnerability was found in MicroPython 1.23.0. It has been rated as critical. Affected by this issue is the function mpz_as_bytes of the file py/objint.c. The manipulation leads to heap-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The patch is identified as 908ab1ceca15ee6fd0ef82ca4cba770a3ec41894. It is recommended to apply a patch to fix this issue. In micropython objint component, converting zero from int to bytes leads to heap buffer-overflow-write at mpz_as_bytes.

Affected Packages

3 total
EcosystemPackageVulnerable rangeFix
🐍PyPImicropython-copyall versionsNo fix
🐍PyPImicropython-ioall versionsNo fix
🐍PyPImicropython-osall versionsNo fix

Affected Products

1 product · 1 configurations
Application
micropythonmicropython
1 version
1.23.0
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for micropython-copy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of micropython-copy for CVE-2024-8948. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

A vulnerability was found in MicroPython 1.23.0. It has been rated as critical. Affected by this issue is the function mpz_as_bytes of the file py/objint.c. The manipulation leads to heap-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The patch is identified as 908ab1ceca15ee6fd0ef82ca4cba770a3ec41894. It is recommended to apply a patch to fix this issue. In micropython objint component, converting zero from int to bytes leads to heap buffer-overflow-write at mpz_as_bytes.
O3 Security · Impact-Aware SCA

Is CVE-2024-8948 in your dependencies?

Find it across PyPI, including transitive dependencies.

CVE-2024-8948: micropython-copy Memory Corruption