Instances deployed via the Proxmox extension allow unauthorized access to instances belonging to other tenants.




This issue affects Apache CloudStack: from 4.21.0.0 through 4.22.0.0.




The Proxmox extension for CloudStack improperly uses a user-editable instance setting, proxmox_vmid, to associate CloudStack instances with Proxmox virtual machines. Because this value is not restricted or validated against tenant ownership and Proxmox VM IDs are predictable, a non-privileged attacker can modify the setting to reference a VM belonging to another account. This allows unauthorized cross-tenant access and enables full control over the targeted VM, including starting, stopping, and destroying the virtual machine.




Users are recommended to upgrade to version 4.22.0.1, which fixes this issue.




As a workaround for the existing installations, editing of the proxmox_vmid instance detail by users can be prevented by adding this detail name to the global configuration parameter - user.vm.denied.details.

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Fri, 08 May 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 08 May 2026 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache cloudstack
Vendors & Products Apache
Apache cloudstack

Fri, 08 May 2026 13:00:00 +0000

Type Values Removed Values Added
Description Instances deployed via the Proxmox extension allow unauthorized access to instances belonging to other tenants. This issue affects Apache CloudStack: from 4.21.0.0 through 4.22.0.0. The Proxmox extension for CloudStack improperly uses a user-editable instance setting, proxmox_vmid, to associate CloudStack instances with Proxmox virtual machines. Because this value is not restricted or validated against tenant ownership and Proxmox VM IDs are predictable, a non-privileged attacker can modify the setting to reference a VM belonging to another account. This allows unauthorized cross-tenant access and enables full control over the targeted VM, including starting, stopping, and destroying the virtual machine. Users are recommended to upgrade to version 4.22.0.1, which fixes this issue. As a workaround for the existing installations, editing of the proxmox_vmid instance detail by users can be prevented by adding this detail name to the global configuration parameter - user.vm.denied.details.
Title Apache CloudStack: Proxmox Extension Allows Unauthorized Cross-Tenant Instance Access
Weaknesses CWE-200
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-05-08T17:46:13.532Z

Reserved: 2026-01-30T04:45:03.322Z

Link: CVE-2026-25199

cve-icon Vulnrichment

Updated: 2026-05-08T17:24:21.520Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-05-08T13:16:36.273

Modified: 2026-05-08T18:16:33.333

Link: CVE-2026-25199

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-08T16:15:12Z

Weaknesses