GHSA-v5q5-3vcq-49r5
Severity by source
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
Network-accessible API requires low-privilege tenant auth (PR:L); cross-project impact means scope change (S:C); integrity of victim subnets is highly impacted, confidentiality and availability are limited.
Primary rating from Vendor (CNA).
CVSS VectorVendor
Lifecycle Timeline
2Description PRE-NVD
AnalysisAI
Cross-project subnet mutation in OpenStack Neutron's subnetpool onboarding feature allows an authenticated tenant to modify subnets belonging to other projects, breaking multi-tenancy isolation. Affected releases span 2025.1/epoxy through the in-development 2026.2/hibiscus branch. No public exploit code has been identified at time of analysis, and CISA KEV listing is absent, but the multi-tenant nature of the affected deployments elevates real-world impact for shared cloud environments.
Technical ContextAI
OpenStack Neutron is the networking-as-a-service component of OpenStack, responsible for managing virtual networks, subnets, and subnet pools across tenant projects. Subnet pools allow projects to allocate subnets from a shared address range. The 'subnetpool onboarding' workflow - which associates existing subnets with a pool - contains an authorization deficiency that permits a project to mutate subnet resources owned by a different project. The root cause class is an improper authorization check (consistent with CWE-284 Improper Access Control or CWE-863 Incorrect Authorization), where the onboarding code path does not enforce project ownership boundaries before applying changes. No CWE was formally assigned in the available advisory data. Patches targeting four release branches (epoxy, flamingo, gazpacho, hibiscus) have been submitted as Gerrit reviews on review.opendev.org.
RemediationAI
Upstream fix is available (PR/commit); released patched version not independently confirmed. Operators should apply the branch-specific Gerrit patches - review.opendev.org/999134 for epoxy, review.opendev.org/999133 for flamingo, review.opendev.org/999132 for gazpacho, and review.opendev.org/999131 for hibiscus - by tracking the merge status and updating from distribution packages once packaged. If immediate patching is not possible, restrict access to the Neutron subnetpool onboarding API endpoint through OpenStack policy.json or oslo.policy rules to limit which roles and projects can invoke onboarding operations; narrowing this to cloud-admin-only trades the self-service convenience of subnetpool onboarding for containment of the cross-project mutation risk. Monitor the OpenStack Security Advisory page at security.openstack.org and the Launchpad bug at bugs.launchpad.net/bugs/2152113 for updated patch availability. No workaround eliminates the flaw without API restriction.
Same weakness CWE-863 – Incorrect Authorization
View allSame technique Authentication Bypass
View allVendor StatusVendor
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-53046