CVE-2025-66171: Apache Cloudstack

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

The CloudStack Backup plugin has an improper access logic in versions 4.21.0.0 and 4.22.0.0. Anyone with authenticated user-account access in CloudStack 4.21.0.0+ environments, where this plugin is enabled and have access to specific APIs can create new VMs using backups of any other user of the environment. Backup plugin users using CloudStack 4.21.0.0+ are recommended to upgrade to CloudStack version 4.22.0.1, which fixes this issue.

Affected products

• Apache Cloudstack: from 4.21.0.0, before 4.22.0.1 (fixed in 4.22.0.1)

Published 2026-05-08. Last modified 2026-10-07.