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No exploitation reportedFix available

CVE-2021-33430

No exploitation reported by the sources we read.

  • Published2021-12-17
  • Fixed in1.21 · 1.10.0
  • WeaknessCWE-120

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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

Timeline

dates in UTC
  1. 2021-12-1719:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-33430?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-33430?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD
numpy
BranchAffectedFixed in
1.x≥ 1.9.0, < 1.211.21
1.x≥ 1.9.0, < 1.10.01.10.0
Numpy
BranchAffectedFixed in
1.9≥ 1.9.0, ≤ 1.9.3no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2021-33430 Red Hat Product Security18 products fixed · 22 known affected

    numpy: buffer overflow in the PyArray_NewFromDescr_int() in ctors.c

    numpy.src as a component of Red Hat Enterprise Linux 8 · numpy.src (inkscape:flatpak) as a component of Red Hat Enterprise Linux 8 · numpy.src (python27:2.7) as a component of Red Hat Enterprise Linux 8 · +19 more

  • RHSA-2022:0987 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.1 (numpy) security update

  • RHSA-2022:1000 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.2 (numpy) security update

Full record on NVD

Fix

  1. Update numpy to 1.21 · 1.10.0
  2. Vendor fix Red Hat Product Security RHSA-2022:0987 · 27 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. No fix available, says the vendor Red Hat Product Security CVE-2021-33430 · 2 productsAffected
  4. No fix planned, says the vendor Red Hat Product Security CVE-2021-33430 · 2 productsOut of support scope
  5. No fix planned, says the vendor Red Hat Product Security CVE-2021-33430 · 18 productsWill not fix

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2024-05-01
  • OpenCVESSVC decisionnone—
  • NVDCVSS 3.15.3read 2026-10-23
  • NVDCVSS 2.03.5read 2026-10-23
  • NVDweakness (CWE)CWE-120read 2026-10-23
  • FIRST EPSSEPSS score1.2 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Published
2021-12-17
Last Modified
2026-06-17
NVD status
Modified

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

Is CVE-2021-33430 actively exploited?

Active exploitation of CVE-2021-33430 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-33430?

CVE-2021-33430 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.

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