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Fencer Intel
high 7.1

CVE-2026-55707 json

In OpenStack Neutron before 28.0.2, the subnetpool onboarding API does not verify ownership of the target subnets.

published 3mo ago modified 18d ago also EUVD-2026-53046

cvss
7.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

In OpenStack Neutron before 28.0.2, the subnetpool onboarding API does not verify ownership of the target subnets. An authenticated user can onboard subnets from another project's shared network into their own subnetpool, mutating the victim's subnet state and altering L3 routing and address scope behavior for victim routers.

Patch / fix

  • OpenStack Neutron 26.0.6, 27.0.4, 28.0.2
  • neutron Debian 12 2:21.0.0-7+deb12u1
  • neutron Debian 13 2:26.0.3-0+deb13u3
  • neutron Debian 14 2:28.0.1-2

debian advisories DEBIAN-CVE-2026-55707

Is CVE-2026-55707 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55707 updated cvss 7.1

openstack-neutron: openstack-neutron: Shared-network consumer can re-scope another project's subnets via subnetpool onboarding

  • Red Hat OpenStack Platform 16.2 python3-neutron, openstack-neutron, openstack-neutron-ml2, openstack-neutron-common, openstack-neutron-rpc-server, openstack-neutron-linuxbridge, +4 more Red Hat OpenStack Platform 17.1 python3-neutron, openstack-neutron, openstack-neutron-ml2, openstack-neutron-common, openstack-neutron-rpc-server, openstack-neutron-bgp-dragent, +7 more Red Hat OpenStack Platform 18.0 openstack-neutron
    affected: workaround, no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • OpenStack Neutron

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.