CVE-2021-41495: Null Pointer Dereference vulnerability exists in numpy.sort in NumPy &lt and 1.19 in the PyArray_DescrNew func

Q: How do I fix CVE-2021-41495?

numpy: upgrade to newer than 1.19.0. Exact commands for each OS are on this page.

Q: Is CVE-2021-41495 being exploited?

CVE-2021-41495 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-41495 affect?

CVE-2021-41495 affects numpy. Severity is medium (CVSS 5.3). Null Pointer Dereference vulnerability exists in numpy.sort in NumPy &lt and 1.19 in the PyArray_DescrNew function due to missing return-value validation, which allows attackers to conduct DoS attacks by repetitively creating sort arrays. N

Q: How urgent is CVE-2021-41495?

Priority 41/100. Public exploit reference

This month

MEDIUM 5.3UPGRADE

CVE-2021-41495 is a medium-severity flaw (CVSS 5.3) affecting numpy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Null Pointer Dereference vulnerability exists in numpy.sort in NumPy &lt and 1.19 in the PyArray_DescrNew function due to missing return-value validation, which allows attackers to conduct DoS attacks by repetitively creating sort arrays. NOTE: While correct that validation is missing, an error can only occur due to an exhaustion of memory. If the user can exhaust memory, they are already privileged. Further, it should be practically impossible t

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-476
Published	2021-12-17
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: numpy

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-12-17 20:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

numpy numpy UPGRADE

Affected: <= 1.19.0

Fixed in: newer than 1.19.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy numpy || rpm -q numpy || numpy --version

2. UPGRADE to newer than 1.19.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade numpy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade numpy

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-41495?

numpy: upgrade to newer than 1.19.0. Exact commands for each OS are on this page.

Is CVE-2021-41495 being exploited?

CVE-2021-41495 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-41495 affect?

CVE-2021-41495 affects numpy. Severity is medium (CVSS 5.3). Null Pointer Dereference vulnerability exists in numpy.sort in NumPy &lt and 1.19 in the PyArray_DescrNew function due to missing return-value validation, which allows attackers to conduct DoS attacks by repetitively creating sort arrays. N

How urgent is CVE-2021-41495?

Priority 41/100. Public exploit reference

Software pages

Pandas and NumPy vulnerabilities

Related CVEs

CVE-2021-34141 MEDIUM 5.3 UPGRADE DOWNGRADE An incomplete string comparison in the numpy.core component in NumPy before 1.22.0 allows attackers to trigger
CVE-2021-41496 MEDIUM 5.5 UPGRADE Buffer overflow in the array_from_pyobj function of fortranobject.c in NumPy < 1.19, which allows attackers to
CVE-2021-33430 MEDIUM 5.3 UPGRADE A Buffer Overflow vulnerability exists in NumPy 1.9.x in the PyArray_NewFromDescr_int function of ctors.c when
CVE-2019-6446 CRITICAL 9.8 UPGRADE MITIGATE An issue was discovered in NumPy before 1.16.3
CVE-2017-12852 HIGH 7.5 UPGRADE The numpy.pad function in Numpy 1.13.1 and older versions is missing input validation

References

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