CVE-2026-55707 Missing authorization in Neutron
An authenticated user can onboard subnets from another project's shared network into their own subnetpool, altering victim routing and address scope.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55707?
CVE-2026-55707 is a high-severity missing authorization vulnerability in OpenStack Neutron, published on 5 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-863
Which versions are affected by CVE-2026-55707?
How do I fix CVE-2026-55707?
Upgrade to a fixed version.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-55707 being exploited?
There is no known exploitation of CVE-2026-55707 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-55707, GHSA-v5q5-3vcq-49r5, UBUNTU-CVE-2026-55707.