Security advisory
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
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-33430
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:47 UTC · Revision 1
Source evidence
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"
}