CVE-2021-33430

Exp

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

Published: 2021-12-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

NVD Status：Modified，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2021-33430

EPSS CVSS CWE GHSA Exploit-DB Affected OS Tracker

Conclusion & alert: CVE-2021-33430 is rated Exploit Available (58.3/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.07%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-33430

EDB-ID	Source	Kind	Published	Link
—	nvd_ref	exploit_tag		Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-33430

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.17%	1.07%	+0.90%
2	2026-03-20	0.59%	0.17%	-0.42%
3	2025-12-10	—	0.59%	—

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-33430

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.6	3.6	[email protected]
3.5	2.0	LOW	`AV:N/AC:M/Au:S/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:S) A single authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	6.8	2.9	[email protected]

Weakness enumeration for CVE-2021-33430

CWE-120 MITRE ↗

GitHub Security Advisory for CVE-2021-33430

GHSA-6p56-wp2h-9hxr · Severity: medium · Ecosystem: pip — NumPy Buffer Overflow (Disputed)

OS Trackers for CVE-2021-33430

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2021-33430 not yet assigned priority: Debian including 1 source packages (numpy), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1.	https://security-tracker.debian.org/tracker/CVE-2021-33430
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-33430
`suse`	high	CVE-2021-33430 severity important: SUSE including 301 source package names (1.1.1.0.1.5.568:python3-numpy-1.17.3-10.1, 1.2.0.0.1.5.583:python3-numpy-1.17.3-10.1, …), 468 product×package rows across 51 product lines (Container ses/6/cephcsi/cephcsi, Container ses/6/rook/ceph, … (51 product lines)): Fixed 233, Known Affected 231, Known Not Affected 4.	https://www.suse.com/security/cve/CVE-2021-33430/
`ubuntu`	medium	CVE-2021-33430 medium priority: Ubuntu including 1 source packages (numpy), 8 status rows across 8 suites (focal, hirsute, impish, jammy, kinetic, trusty, upstream, xenial): ignored 4, not-affected 2, released 2.	https://ubuntu.com/security/CVE-2021-33430

Affected software / configurations for CVE-2021-33430

Vendor	Product	Version	Raw CPE
numpy	numpy	>= 1.9.0, <= 1.9.3	cpe:2.3:a:numpy:numpy::::::::

References for CVE-2021-33430

URL	Tags
https://github.com/numpy/numpy/issues/18939	Exploit Third Party Advisory

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