An issue was discovered in OpenStack Cinder through 24.0.0, Glance before 28.0.2, and Nova before 29.0.3. Arbitrary file access can occur via custom QCOW2 external data. By supplying a crafted QCOW2 image that references a specific data file path, an authenticated user may convince systems to return a copy of that file's contents from the server, resulting in unauthorized access to potentially sensitive data. All Cinder and Nova deployments are affected; only Glance deployments with image conversion enabled are affected.