CVE-2026-66721

Account users are allowed by default to register templates to be downloaded directly to the primary storage for deploying instances using the KVM hypervisor. Due to missing file name sanitization, an attacker can register malicious templates to execute arbitrary code on the KVM hosts.

Missing MinIO policy cleanup on bucket deletion via Apache CloudStack allows users to retain access to buckets which they previously owned. If another user creates a new bucket with the same name, the previous owners can gain unauthorized read and write access to it.

Improper Access Control vulnerability in Apache CloudStack's Kubernetes Service (CKS) plugin, allowing cross-tenant manipulation of the Kubernetes cluster while adding and removing nodes. Affects versions from 4.21.0.0 through 4.22.1.0.

Improper Encoding or Escaping of Output vulnerability in Apache CloudStack's UI while using Instance Reset Password functionality. Affects versions from 4.15.1.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0.

Server-Side Request Forgery (SSRF) vulnerability in Apache CloudStack's webhook module, exploitable via webhook delivery requests. Affects versions from 4.20.0.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0.

The Proxmox extension for Apache CloudStack allows unauthorized access to instances belonging to other tenants. The issue arises from improper use of an instance setting, enabling attackers to modify and gain control over virtual machines of other users.

Apache CloudStack before version 4.5.2 does not properly preserve VNC passwords when migrating KVM virtual machines, allowing remote attackers to gain access by connecting to the VNC server.

Apache CloudStack versions 4.7.0 through 4.20.3.0 and 4.21.0.0 through 4.22.1.0 have a missing release of resource after effective lifetime vulnerability in the scoped global configuration functionality. This may lead to denial of service (DoS) for the management server.

Certificate validation failures in SAML authentication in Apache CloudStack 4.20.3.0 and 4.22.1.0 allow a malicious agent to forge a SAML response to the management server. The agent must spoof the IdP IP address or register a URL of its own choosing, after which it can allow logging on with forged signatures. Users are recommended to upgrade to versions 4.20.3.1 or 4.22.1.1 and above.

Improper access control in CloudStack's annotation functionality allows unauthorized comment creation and disclosure. The addAnnotation and listAnnotation APIs perform an ownership check but fail to honor its result correctly, allowing any authenticated user to write and read annotations on entities they don't own. Affects versions from 4.15.0.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0.