CVE-2021-40797

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-09-08 · updated 2026-06-17
Weakness: CWE-772

Description

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.

Affected products

OpenStack Neutron: before 16.4.1; from 17.0.0 before 17.2.1; from 18.0.0 before 18.1.1 — fixed in 16.4.1, 17.2.1, 18.1.1

How to fix

Upgrade to a fixed version: OpenStack Neutron 16.4.1, 17.2.1, 18.1.1. Check the vendor advisory for mitigations.

References

http://www.openwall.com/lists/oss-security/2021/09/09/2
https://launchpad.net/bugs/1942179
https://security.openstack.org/ossa/OSSA-2021-006.html
http://www.openwall.com/lists/oss-security/2021/09/09/2
https://launchpad.net/bugs/1942179
https://security.openstack.org/ossa/OSSA-2021-006.html

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