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No exploitation reportedFix available

CVE-2021-40797

No exploitation reported by the sources we read.

  • Published2021-09-08
  • Fixed in18.1.1 · 17.2.1 · 16.4.1
  • WeaknessCWE-772

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-09-0820:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-40797?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-40797?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Openstack neutron
BranchAffectedFixed in
18.x≥ 18.0.0, < 18.1.118.1.1
17.x≥ 17.0.0, < 17.2.117.2.1
16.4< 16.4.116.4.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2021-40797 Red Hat Product Security22 products fixed · 37 known affected

    openstack-neutron: Routes middleware memory leak for nonexistent controllers

    openstack-neutron as a component of Red Hat OpenStack Platform 10 (Newton) · openstack-neutron-common as a component of Red Hat OpenStack Platform 10 (Newton) · openstack-neutron-linuxbridge as a component of Red Hat OpenStack Platform 10 (Newton) · +34 more

  • RHSA-2022:0990 Red Hat Product Security11 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.1 (openstack-neutron) security update

  • RHSA-2022:0996 Red Hat Product Security11 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.2 (openstack-neutron) security update

Full record on NVD

Fix

  1. Update Openstack neutron to 18.1.1 · 17.2.1 · 16.4.1
  2. Vendor fix Red Hat Product Security RHSA-2022:0990 · 11 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. Workaround from the vendor Red Hat Product Security RHSA-2022:0990 · 11 productsMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
  4. No fix available, says the vendor Red Hat Product Security CVE-2021-40797 · 1 productFix deferred
  5. No fix planned, says the vendor Red Hat Product Security CVE-2021-40797 · 36 productsOut of support scope

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.16.5read 2026-10-23
  • NVDCVSS 2.04read 2026-10-23
  • NVDweakness (CWE)CWE-772read 2026-10-23
  • FIRST EPSSEPSS score1.8 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Published
2021-09-08
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is 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. 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.

Is CVE-2021-40797 actively exploited?

Active exploitation of CVE-2021-40797 has not been confirmed. Its EPSS score was 1.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-40797?

CVE-2021-40797 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

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