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9.4
CVE-2026-23561: XenServer Role-Based Access Control Settings Not Fully Restricted
CVE-2026-23561
CVE-2026-23561
Summary
XenServer's role-based access control settings are not fully restricted, allowing lower-privileged administrators to make changes they shouldn't be able to. This could allow an unauthorized user to access or modify sensitive files, mark a VM as a system domain, or cause issues with storage connections. Update your XenServer configuration to ensure that settings are properly restricted to prevent unauthorized access and changes.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| xen | xapi | all |
Original title
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]
XAPI can configure different users with different roles, using Role
...
Original description
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]
XAPI can configure different users with different roles, using Role
Based Access Control. For more details, see:
https://docs.xenserver.com/en-us/xencenter/current-release/rbac-overview.html#rbac-roles
The pool-admin role is fully privileged. Notably, users with this role
can also SSH into the host as root.
The other administrator roles are pool-operator, vm-power-admin and
vm-admin, each of which are authorised to configure and manage various
aspects of the system.
Some settings are inadequately restricted, and can be set by a lower
privilege of administrator than expected.
* CVE-2026-23559: A vm-admin can set VBD.other_config:backend-local and
turn arbitrary files in dom0 into VDIs (virtual disks) and give said
disks to a VM they control. This is an arbitrary read and/or modify
of files in dom0.
* CVE-2026-23560: A vm-admin can set VM.other-config:is_system_domain
and mark a VM as a system domain. System domains are ignored and
left running during certain other host/pool operations, and may be
hidden from view in tooling.
* CVE-2026-23561: A vm-admin can set VM.other_config:storage_driver_domain
and mark a VM as the storage domain for a particular host storage
connection (PBD). Shutting down the VM can cause the PBD to be
erroneously marked as unplugged when it is not.
* CVE-2026-23562: Configuration of PCI passthrough is normally
restricted to the pool-admin role. However one API was missing this
check, allowing a vm-admin access to unintended host hardware.
* CVE-2026-42486: A vm-admin can set the VM.platform:hvm_serial
parameter, which should be restricted to the pool-admin role, as it
can allow arbitrary dom0 file write.
XAPI can configure different users with different roles, using Role
Based Access Control. For more details, see:
https://docs.xenserver.com/en-us/xencenter/current-release/rbac-overview.html#rbac-roles
The pool-admin role is fully privileged. Notably, users with this role
can also SSH into the host as root.
The other administrator roles are pool-operator, vm-power-admin and
vm-admin, each of which are authorised to configure and manage various
aspects of the system.
Some settings are inadequately restricted, and can be set by a lower
privilege of administrator than expected.
* CVE-2026-23559: A vm-admin can set VBD.other_config:backend-local and
turn arbitrary files in dom0 into VDIs (virtual disks) and give said
disks to a VM they control. This is an arbitrary read and/or modify
of files in dom0.
* CVE-2026-23560: A vm-admin can set VM.other-config:is_system_domain
and mark a VM as a system domain. System domains are ignored and
left running during certain other host/pool operations, and may be
hidden from view in tooling.
* CVE-2026-23561: A vm-admin can set VM.other_config:storage_driver_domain
and mark a VM as the storage domain for a particular host storage
connection (PBD). Shutting down the VM can cause the PBD to be
erroneously marked as unplugged when it is not.
* CVE-2026-23562: Configuration of PCI passthrough is normally
restricted to the pool-admin role. However one API was missing this
check, allowing a vm-admin access to unintended host hardware.
* CVE-2026-42486: A vm-admin can set the VM.platform:hvm_serial
parameter, which should be restricted to the pool-admin role, as it
can allow arbitrary dom0 file write.
Vulnerability type
CWE-250
Published: 9 Jul 2026 · Updated: 10 Jul 2026 · First seen: 9 Jul 2026