CVE-2026-55707 in Neutron
Summary
by MITRE • 08/05/2026
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.
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Analysis
by VulDB Data Team • 08/17/2026
This vulnerability exists in OpenStack Neutron versions prior to 28.0.2 and represents a critical authorization flaw that undermines the fundamental security boundaries between projects within the cloud infrastructure. The issue stems from the subnetpool onboarding API failing to properly validate ownership permissions when processing requests to incorporate existing subnets into new subnetpools. This technical deficiency allows an authenticated malicious user to exploit the system by submitting requests that reference subnets belonging to different projects, effectively bypassing the multi-tenant isolation mechanisms that should protect each project's network resources from unauthorized access or modification.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it directly compromises the integrity of network routing configurations and address scope management across shared network environments. When an attacker successfully onboards subnets from another project into their own subnetpool, they fundamentally alter the network state of the victim project's routers, potentially causing routing failures, address conflicts, or unauthorized network access patterns. This modification affects Layer 3 routing behavior and can disrupt critical network services that depend on proper address scope management within the OpenStack environment.
From a cybersecurity perspective, this vulnerability aligns with CWE-284 Access Control Issues and represents a clear violation of the principle of least privilege that should govern all cloud infrastructure components. The flaw enables what security analysts would classify as a privilege escalation attack vector through unauthorized resource manipulation, where an attacker can effectively take control of network state management for resources they should not have access to. This vulnerability also relates to ATT&CK technique T1078 Valid Accounts, as it leverages legitimate authentication mechanisms to perform unauthorized operations within the system.
The mitigation strategy requires immediate patching of OpenStack Neutron to version 28.0.2 or later, which implements proper ownership verification checks within the subnetpool onboarding API. Organizations should also implement additional monitoring and alerting around subnetpool modifications and cross-project subnet references to detect potential exploitation attempts. Network administrators should review and tighten authorization policies for subnetpool operations, ensuring that only authorized project members can perform onboarding activities and that proper audit trails are maintained for all network state changes. Additionally, implementing network segmentation and regular security assessments of shared network resources will help prevent similar vulnerabilities from manifesting in other components of the cloud infrastructure ecosystem.