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Medium

Security advisory

Type: advisorySources: OSVCVE: 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

Products
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Affected versions
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Fixed versions
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CVEs
CVE-2021-33430
Confirmed fixed CVEs
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Updated in this feed
31 Oct 2026, 11:47 UTC · Revision 1

Source evidence

CVE-2021-33430

core-osv · Original source

Published 17 Dec 2021, 19:15 UTC

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

osv:CVE-2021-33430
Complete source record
{
  "id": "1c4e3c1455c15bd0762613c8738687cfda226d47854a4d1f740b6d72a3e7cba5",
  "url": "https://osv.dev/vulnerability/CVE-2021-33430",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-33430",
    "summary": "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",
    "evidence": "osv:CVE-2021-33430",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-33430",
      "aliases": [
        "CVE-2021-33430",
        "GHSA-6p56-wp2h-9hxr",
        "PYSEC-2021-854"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/numpy/numpy",
              "type": "GIT",
              "events": [
                {
                  "introduced": "07601a64cdfeb1c0247bde1294ad6380413cab66"
                },
                {
                  "last_affected": "edb902cdc6573553afcf11047ecdfb447e444322"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:numpy:numpy:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.9.0"
                      },
                      {
                        "last_affected": "1.9.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.9.3",
            "v1.9.2",
            "v1.9.2rc1",
            "v1.9.1",
            "v1.9.1rc1",
            "v1.9.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-33430.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:43.847056388Z",
      "provider": "osv",
      "references": [
        "https://github.com/numpy/numpy/issues/18939"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-33430",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 386018,
  "published_at": "2021-12-17T19:15:07.5+00:00"
}