Critical [CVE-2026-25199] Instances deployed via the Proxmox extension allow unauthorized access to instances belonging to other tenants
This critical-severity Proxmox advisory covers CVE-2026-25199; related products: Proxmox.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Android app · Google Play
Monitor future Proxmox CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 34 official vendor sources and 160+ reviewed platform categories.
Summary
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.
- through 4.22.0.0
NVD record · high-confidence parse· fetched 3 months ago·verify at source
Mitigation checklist
- Users are recommended to upgrade to version 4.22.0.1, which fixes this issue.
NVD record · high-confidence parse· fetched 3 months ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.