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Vulnerability record · CVE-2021-33430 · published 17 December 2021

CVE-2021-33430: Numpy classic buffer overflow vulnerability

Numpy · Numpy

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

5.3 CVSS 3.1 Medium EPSS 1.1% · top 36.4% CWE-120 · Classic buffer overflow
5.3CVSS 3.1 base score, v2 3.5
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/numpy/numpy/issues/18939 ExploitThird Party Advisory
https://github.com/numpy/numpy/issues/18939 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-33430), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.