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Not in CISA KEV
HIGH severity

NumPy NULL Pointer DereferenceGHSA-5545-2q6w-2gh6

HIGH

GHSA-5545-2q6w-2gh6 is a high-severity (CVSS 7.5) NULL Pointer Dereference vulnerability in numpy. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for numpy — see the affected versions and patch details below.

Also known asCVE-2021-41495PYSEC-2021-856
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk
0.00%0.58%1.16%1.74%0.1%1.2%1.2%1.2%1.2%Jun 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐍numpy

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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 to construct an attack which can target the memory exhaustion to occur at exactly this place

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPInumpyall versions1.19pip install --upgrade 'numpy==1.19'

Affected Products

1 product · 1 configurations
Application
numpynumpy
≤ 1.19.0
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Null Pointer Dereference vulnerability exists in numpy.sort in NumPy &lt…

github.comNVDDec 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for numpy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update numpy to 1.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5545-2q6w-2gh6 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate
ProductFixed inAdvisory
Red Hat OpenStack Platform 16.1numpy-1:1.17.0-11.el8ostRHSA-2022:8861
Red Hat OpenStack Platform 16.2numpy-1:1.17.0-11.el8ostRHSA-2022:8852

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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NumPy NULL Pointer Dereference (High 7.5)