How severe is CVE-2024-8946?

No CVSS score has been assigned to CVE-2024-8946 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-8946?

CVE-2024-8946 affects the following packages: micropython-copy (PyPI), micropython-io (PyPI), micropython-os-path (PyPI), micropython-string (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2024-8946?

The records we use list no patched version of micropython-copy for CVE-2024-8946. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

How do I detect CVE-2024-8946 in my PyPI dependencies?

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.

How do I mitigate CVE-2024-8946 if there is no patch (or I can't update yet)?

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.

Is CVE-2024-8946 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2024-8946, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2024-8946?

CVE-2024-8946 has an EPSS (Exploit Prediction Scoring System) score of 1.0%, placing it in the 63th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-8946?

CVE-2024-8946 is classified as CWE-122 (CWE-122), Out-of-bounds Write (CWE-787). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-8946 published, and has it been updated?

CVE-2024-8946 was published on September 17, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2024-8946 — micropython-copy

Fix: micropython/micropython@2994354

CVE-2024-8946 is a CWE-122 vulnerability in micropython-copy. 2 public exploit or proof-of-concept references are 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 VFS Unmount vfs.c mp_vfs_umount heap-based overflow

Also known asGHSA-74qm-4v7r-jw2fPYSEC-2024-91PYSEC-2024-93PYSEC-2024-95PYSEC-2024-96

Published

Sep 17, 2024

Updated

Oct 28, 2026

Affected

4 pkgs

Patched

See advisory

Exploits

2 known

Exploitation data as of Nov 6, 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-2024-8946.

EPSS Exploitation Probability

via FIRST.org ↗

1.0%probability of exploitation in next 30 days

Lower Risk-0.01%

Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk

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

Real-World Exposure

4 pkgs affected

🐍micropython-copy🐍micropython-io🐍micropython-os-path🐍micropython-string

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 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.

Affected Packages

4 total

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`micropython-copy`	all versions	No fix
🐍PyPI	`micropython-io`	all versions	No fix
🐍PyPI	`micropython-os-path`	all versions	No fix
🐍PyPI	`micropython-string`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

micropythonmicropython

1 version

1.23.0

Exploits & PoCs

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

A vulnerability was found in MicroPython 1.23.0. It has been classified …

github.comNVDSep 2024

Report on github.com

github.comNVDSep 2024

Detection & mitigation playbook

Open-source dependency

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.
Remediation status
The records we use list no patched version of micropython-copy for CVE-2024-8946. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
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

O3 Security · Impact-Aware SCA

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