CVE-2021-41495: Numpy NumPy NULL Pointer Dereference Vulnerability

HIGH
Advisory Identifier: GHSA-5545-2q6w-2gh6
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CVSS 7.5
CWE-476
Published
Advisory Summary

CVE-2021-41495 is a HIGH (CVSS 7.5) numpy null pointer dereference vulnerability (CWE-476: NULL Pointer Dereference) affecting Numpy libraries in the PyPI ecosystem. The issue involves numpy null pointer dereference. Remediation is available by upgrading affected packages to version 1.19.

CVE-2021-41495 at a Glance

CVE Identifier CVE-2021-41495
GHSA Identifier GHSA-5545-2q6w-2gh6
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-476: NULL Pointer Dereference
Affected Product Numpy
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-41495

To remediate this vulnerability, upgrade all affected Numpy dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

numpy fixed: 1.19 
pip install numpy>=1.19
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show numpy

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2021-41495, inspect your installed packages using pip:

pip show numpy

Analyze the terminal output to locate any version of Numpy in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.19), your application is affected.

Note: The pip show numpy command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-476: NULL Pointer Dereference, where the product dereferences a pointer that it expects to be valid but is null. In Numpy, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2021-41495 Affected Numpy Versions

1 component(s)
Fixed Versions:
1.19
Product / Package Ecosystem Affected Versions Fixed Version
numpy
pypi/numpy
PyPI
< 1.19
1.19

References

NVD — CVE-2021-41495 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-41495
Numpy Source Repository REPOSITORY
https://github.com/numpy/numpy/issues/19038
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-5545-2q6w-2gh6
Numpy Source Repository REPOSITORY
https://github.com/numpy/numpy
Numpy Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/numpy/PYSEC-2021-856.yaml
Numpy Security Information SECURITY
https://www.oracle.com/security-alerts/cpujul2022.html

Frequently Asked Questions

What is CVE-2021-41495?
CVE-2021-41495 is a security vulnerability in Numpy involving NumPy NULL Pointer Dereference under CWE-476: NULL Pointer Dereference.
Which Numpy versions are affected?
Affected versions include releases prior to 1.19 across affected packages: numpy.
What version fixes CVE-2021-41495?
Upgrading to 1.19 (or the latest patched release for your respective branch) resolves the vulnerability.
Is numpy affected?
Yes, numpy is affected in releases prior to 1.19. Upgrade your dependency to 1.19 or later.
What is the CVSS score of CVE-2021-41495?
CVE-2021-41495 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-41495?
CVE-2021-41495 is classified under CWE-476: NULL Pointer Dereference (The product dereferences a pointer that it expects to be valid but is NULL.).
How can I check PyPI dependencies for CVE-2021-41495?
Run the dependency tree command: 'pip show numpy'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5545-2q6w-2gh6",
  "modified" : "2022-08-10T22:18:31Z",
  "published" : "2022-02-08T00:00:56Z",
  "aliases" : [ "CVE-2021-41495" ],
  "summary" : "NumPy NULL Pointer Dereference",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "numpy"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.19"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.18.5"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-41495"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/numpy/numpy/issues/19038"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-5545-2q6w-2gh6"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/numpy/numpy"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/numpy/PYSEC-2021-856.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://www.oracle.com/security-alerts/cpujul2022.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-476" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-06-21T20:10:22Z",
    "nvd_published_at" : "2021-12-17T20:15:00Z"
  }
}