CVE-2026-50266 is an incorrect authorization vulnerability in OpenStack Neutron before version 28.0.1. It allows a project manager to create or update a port on a shared network owned by another project and set the device_owner attribute to a value prefixed with "network:" (e.g., "network:dhcp"). The default RBAC policies incorrectly include the PROJECT_MANAGER role without requiring ownership of the network, enabling any project manager to obtain trusted network-service port behavior on shared networks. Depending on the backend and deployment, this can bypass anti-spoofing and security group protections, allowing DHCP, MAC, or IP spoofing attacks against other tenants on the shared network. This vulnerability is a regression of CVE-2015-5240 (OSSA-2015-018).

The vulnerability allows project managers to bypass network ownership restrictions on shared networks, potentially enabling spoofing attacks such as DHCP, MAC, or IP spoofing against other tenants. This can undermine network isolation and security group protections. However, the CVSS score of 2.2 and the low severity rating indicate that the impact is limited and requires high privileges (project manager) and specific conditions to exploit.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Until a patch is available, review and tighten RBAC policies related to project managers and shared network port creation. Monitor OpenStack Neutron vendor advisories for updates and apply official fixes once released.