CVE-2024-8948 — micropython-copy
Fix: micropython/micropython@908ab1cCVE-2024-8948 is a CWE-122 vulnerability in micropython-copy. 1 public exploit reference exists, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.
MicroPython objint.c mpz_as_bytes heap-based overflow
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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
micropython-copy🐍micropython-io🐍micropython-osReal-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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | micropython-copy | all versions | No fix |
| 🐍PyPI | micropython-io | all versions | No fix |
| 🐍PyPI | micropython-os | all versions | No fix |
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 dependencyDetect
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.
Remediation status
No patched version of micropython-copy has shipped for CVE-2024-8948 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-8948 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-8948. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-8948 in your dependencies?
O3 Security finds CVE-2024-8948 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.