CVE-2021-20267: Neutron Openstack Neutron Has Insufficient Verification Vulnerability

HIGH
Advisory Identifier: GHSA-w8hx-f868-pvch
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CVSS 7.1
CWE-345
Published
Advisory Summary

CVE-2021-20267 is a HIGH (CVSS 7.1) openstack neutron has insufficient verification vulnerability (CWE-345: Insufficient Verification of Data Authenticity) affecting Neutron libraries in the PyPI ecosystem. The issue involves openstack neutron has insufficient verification of ipv6 addresses. Remediation is available by upgrading affected packages to version 16.3.1, 15.3.3, 17.1.1.

CVE-2021-20267 at a Glance

CVE Identifier CVE-2021-20267
GHSA Identifier GHSA-w8hx-f868-pvch
Severity HIGH
CVSS v3.1 Base Score 7.1
CWE Classification CWE-345: Insufficient Verification of Data Authenticity
Affected Product Neutron
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.1

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

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

How to Fix CVE-2021-20267

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

neutron fixed: 16.3.1 
pip install neutron>=16.3.1
neutron fixed: 15.3.3 
pip install neutron>=15.3.3
neutron fixed: 17.1.1 
pip install neutron>=17.1.1
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 neutron

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2021-20267, inspect your installed packages using pip:

pip show neutron

Analyze the terminal output to locate any version of Neutron in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 16.3.1), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-345: Insufficient Verification of Data Authenticity, where the product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. In Neutron, 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

A flaw was found in openstack-neutron's default Open vSwitch firewall rules. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the IPv6 addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations. Only deployments using the Open vSwitch driver are affected. Source: OpenStack project. Versions before openstack-neutron 15.3.3, openstack-neutron 16.3.1 and openstack-neutron 17.1.1 are affected.

CVE-2021-20267 Affected Neutron Versions

3 component(s)
Fixed Versions:
16.3.115.3.317.1.1
Product / Package Ecosystem Affected Versions Fixed Version
neutron
pypi/neutron
PyPI
≥ 16.0.0
< 16.3.1
16.3.1
neutron
pypi/neutron
PyPI
< 15.3.3
15.3.3
neutron
pypi/neutron
PyPI
≥ 17.0.0
< 17.1.1
17.1.1

References

NVD — CVE-2021-20267 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-20267
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=1934330
Neutron Source Repository REPOSITORY
https://github.com/openstack/neutron
Neutron Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/neutron/PYSEC-2021-136.yaml
Neutron Security Information SECURITY
https://security.openstack.org/ossa/OSSA-2021-001.html

Frequently Asked Questions

What is CVE-2021-20267?
CVE-2021-20267 is a security vulnerability in Neutron involving Openstack Neutron has Insufficient Verification of IPv6 addresses under CWE-345: Insufficient Verification of Data Authenticity.
Which Neutron versions are affected?
Affected versions include releases prior to 16.3.1, 15.3.3, 17.1.1 across affected packages: neutron.
What version fixes CVE-2021-20267?
Upgrading to 16.3.1, 15.3.3, 17.1.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is neutron affected?
Yes, neutron is affected in releases prior to 16.3.1, 15.3.3, 17.1.1. Upgrade your dependency to 16.3.1, 15.3.3, 17.1.1 or later.
What is the CVSS score of CVE-2021-20267?
CVE-2021-20267 has a CVSS v3.1 base score of 7.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H.
What CWE is associated with CVE-2021-20267?
CVE-2021-20267 is classified under CWE-345: Insufficient Verification of Data Authenticity (The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.).
How can I check PyPI dependencies for CVE-2021-20267?
Run the dependency tree command: 'pip show neutron'. 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-w8hx-f868-pvch",
  "modified" : "2024-09-26T14:51:10Z",
  "published" : "2022-05-24T19:03:37Z",
  "aliases" : [ "CVE-2021-20267" ],
  "summary" : "Openstack Neutron has Insufficient Verification of IPv6 addresses",
  "details" : "A flaw was found in openstack-neutron's default Open vSwitch firewall rules. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the IPv6 addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations. Only deployments using the Open vSwitch driver are affected. Source: OpenStack project. Versions before openstack-neutron 15.3.3, openstack-neutron 16.3.1 and openstack-neutron 17.1.1 are affected.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "neutron"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "16.0.0"
      }, {
        "fixed" : "16.3.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "neutron"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "15.3.3"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "neutron"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "17.0.0"
      }, {
        "fixed" : "17.1.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-20267"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1934330"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openstack/neutron"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/neutron/PYSEC-2021-136.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://security.openstack.org/ossa/OSSA-2021-001.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-345" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-02-23T21:28:05Z",
    "nvd_published_at" : "2021-05-28T19:15:00Z"
  }
}