CVE-2021-33430

Process crash via unchecked dimension count

Published Dec 17, 2021 · Updated Aug 3, 2024

Buffer overflow in NumPy 1.9.x allows local users to crash a Python process by requesting an array with more than 32 dimensions. PyArray_NewFromDescr_int in ctors.c copies the requested dimensions and optional strides into fixed NPY_MAXDIMS stack regions without enforcing that limit. Triggering the overwrite requires uncommon structured dtypes and Python-level use of the array-construction API; NumPy disputes the vulnerability and states that such users can already exhaust process memory.

CVSS severity5.3
Medium
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in NumPy 1.9.x allows local users to crash a Python process by requesting an array with more than 32 dimensions. PyArray_NewFromDescr_int in ctors.c copies the requested dimensions and optional strides into fixed NPY_MAXDIMS stack regions without enforcing that limit. Triggering the overwrite requires uncommon structured dtypes and Python-level use of the array-construction API; NumPy disputes the vulnerability and states that such users can already exhaust process memory.

The record

CVE
CVE-2021-33430
Published
Dec 17, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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