CVE-2021-33430: NumPy Buffer Overflow (Disputed)

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-12-17 · updated 2026-06-17
Weakness: CWE-120

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

Affected products

Numpy: from 1.9.0 through 1.9.3
Pypi Numpy: from 1.9.0 before 1.21; 1.10.0, 1.10.1, 1.10.2, 1.10.3, 1.10.4, 1.11.0 (+53) — fixed in 1.21

How to fix

Upgrade to a fixed version: Pypi Numpy 1.21. Check the vendor advisory for mitigations.

References

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