CVE-2026-55707: Openstack Neutron

High severity, CVSS 7.1. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Openstack Neutron: from 14.0.0, before 26.0.6 (fixed in 26.0.6); from 27.0.0, before 27.0.4 (fixed in 27.0.4); from 28.0.0, before 28.0.2 (fixed in 28.0.2)

Published 2026-08-05. Last modified 2026-08-31.