SSRF via Metalink Mirror URL Resolution:

An authenticated tenant can register a template pointing to an attacker-controlled metalink file containing internal targets. The Secondary Storage VM will retrieve the data and persist it as a template file, which can later be downloaded through normal APIs.

RCE on KVM hypervisor via NFS, Metalink files with/without Direct Downloads:

An authenticated CloudStack tenant holding the default User role can execute arbitrary shell commands as root on the KVM hypervisor host that runs other tenants' VMs. This is cross-tenant root on the underlying compute, reachable via the public CloudStack API.

When a User registers a VM template with directDownload=true and a URL pointing to a .metalink file, the management server fetches the metalink XML and dispatches download to the KVM agent. Inner URLs inside the metalink XML are never re-validated against the scheme allowlist.

These issues affect Apache CloudStack: from 4.14.0.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0.

Users are recommended to upgrade to version 4.20.3.1 or 4.22.1.1 or later, which fixes the issue.

A problem has been identified in the CloudStack additional VM configuration (extraconfig) feature which can be misused by anyone who has privilege to deploy a VM instance or configure settings of an already deployed VM instance, to configure additional VM configuration even when the feature is not explicitly enabled by the administrator. In a KVM based CloudStack environment, an attacker can exploit this issue to attach host devices such as storage disks, and PCI and USB devices such as network adapters and GPUs, in a regular VM instance that can be further exploited to gain access to the underlying network and storage infrastructure resources, and access any VM instance disks on the local storage.

Users are advised to upgrade to version 4.18.1.1 or 4.19.0.1, which fixes this issue.