# CVE-2021-40797: OpenStack Neutron Denial of Service vulnerability

Source: https://junglewise.ai/threats/cve-2021-40797-openstack-neutron-denial-of-service-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-09-08  
License: CC BY 4.0 with a link back

CVE-2021-40797 · Severity: low · CVSS 3.1 · Published 2021-09-08

An issue was discovered in the routes middleware in OpenStack Neutron before 16.4.1, 17.x before 17.2.1, and 18.x before 18.1.1. By making API requests involving nonexistent controllers, an authenticated user may cause the API worker to consume increasing amounts of memory, resulting in API performance degradation or denial of service.

Technologies: [neutron (PyPI)](https://junglewise.ai/threats/technologies/pypi-neutron). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2021-40797 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-40797 being exploited in the wild.

**How severe is CVE-2021-40797?** Low severity, with a CVSS score of 3.1, published 8 September 2021.

**Which products and versions are affected?** neutron (PyPI) ECOSYSTEM:introduced=0,fixed=16.4.1, ECOSYSTEM:introduced=0,fixed=16.4.1,introduced=17.0.0,fixed=17.2.1,introduced=18.0.0,fixed=18.1.1.

**Is there a fix for CVE-2021-40797?** Yes. neutron (PyPI): upgrade to 16.4.1, 18.1.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-40797?** Check whether you run neutron (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- neutron (PyPI): upgrade to 16.4.1, 18.1.1 or later

  ```sh
  pip install "neutron>=18.1.1"
  ```


## Affected products

- neutron (PyPI) ECOSYSTEM:introduced=0,fixed=16.4.1, ECOSYSTEM:introduced=0,fixed=16.4.1,introduced=17.0.0,fixed=17.2.1,introduced=18.0.0,fixed=18.1.1

## Identifiers

- CVE-2021-40797
- GHSA-cpx3-696p-3cw9
- PYSEC-2021-329

## Related threats

- [PYSEC-2026-1693 - OpenStack Neutron can use an incorrect ID during policy enforcement](https://junglewise.ai/threats/cve-2024-53916-openstack-neutron-can-use-an-incorrect-id-during-policy)
- [PYSEC-2026-1694 - Denial of service in neutron](https://junglewise.ai/threats/cve-2023-3637-denial-of-service-in-neutron)
- [PYSEC-2026-855 - openstack-neutron uncontrolled resource consumption flaw](https://junglewise.ai/threats/cve-2022-3277-openstack-neutron-uncontrolled-resource-consumption-flaw)
- [PYSEC-2026-851 - OpenStack Neutron Improper Authentication vulnerability](https://junglewise.ai/threats/cve-2014-0056-openstack-neutron-improper-authentication-vulnerability)
- [PYSEC-2026-853 - OpenStack Neutron Race condition vulnerability](https://junglewise.ai/threats/cve-2015-5240-openstack-neutron-race-condition-vulnerability)