How severe is CVE-2021-33430?

CVE-2021-33430 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-33430 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33430?

CVE-2021-33430 affects Numpy. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33430?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-33430 published?

CVE-2021-33430 was published on 2021-12-17 and last updated on 2026-06-17.

CVE-2021-33430

CVE-2021-33430 is a medium-severity vulnerability in Numpy with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 3.5
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Numpy
Published: 2021-12-17
Last modified: 2026-06-17

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

Frequently asked questions

What is 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 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
How severe is CVE-2021-33430?: CVE-2021-33430 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-33430 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33430?: CVE-2021-33430 affects Numpy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33430?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-33430 published?: CVE-2021-33430 was published on 2021-12-17 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:numpy:numpy:*:*:*:*:*:*:*:*

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