CVE-2026-23561: CWE-250 Execution with unnecessary privileges in Xen XAPI
[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.
AI Analysis
Technical Summary
XAPI uses Role Based Access Control to assign different privileges to users. The pool-admin role is fully privileged, while vm-admin and other administrator roles have restricted privileges. CVE-2026-23561 arises because a vm-admin can set the VM.other_config:storage_driver_domain parameter, which should be restricted. This allows the vm-admin to mark a VM as the storage domain for a particular host storage connection (PBD). When the VM is shut down, the PBD may be erroneously marked as unplugged despite still being connected, potentially disrupting storage availability or management operations. This vulnerability is one of several privilege escalation or misconfiguration issues in XAPI allowing lower privileged roles to perform unauthorized actions.
Potential Impact
An attacker with vm-admin privileges can manipulate storage domain assignments, causing host storage connections to be incorrectly marked as unplugged. This can lead to storage management inconsistencies, potential disruption of storage operations, and may affect the stability or availability of virtualized storage resources. The vulnerability does not require user interaction and has a local attack vector with low complexity but results in high impact on confidentiality, integrity, and availability as per the CVSS 4.0 score of 9.4.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict vm-admin role assignments to trusted users only and monitor for unusual storage domain configurations. Review role permissions and consider limiting the ability to set VM.other_config parameters to higher privileged roles if possible.
CVE-2026-23561: CWE-250 Execution with unnecessary privileges in Xen XAPI
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.
CVSS v4.0
Score 9.4critical
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
XAPI uses Role Based Access Control to assign different privileges to users. The pool-admin role is fully privileged, while vm-admin and other administrator roles have restricted privileges. CVE-2026-23561 arises because a vm-admin can set the VM.other_config:storage_driver_domain parameter, which should be restricted. This allows the vm-admin to mark a VM as the storage domain for a particular host storage connection (PBD). When the VM is shut down, the PBD may be erroneously marked as unplugged despite still being connected, potentially disrupting storage availability or management operations. This vulnerability is one of several privilege escalation or misconfiguration issues in XAPI allowing lower privileged roles to perform unauthorized actions.
Potential Impact
An attacker with vm-admin privileges can manipulate storage domain assignments, causing host storage connections to be incorrectly marked as unplugged. This can lead to storage management inconsistencies, potential disruption of storage operations, and may affect the stability or availability of virtualized storage resources. The vulnerability does not require user interaction and has a local attack vector with low complexity but results in high impact on confidentiality, integrity, and availability as per the CVSS 4.0 score of 9.4.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict vm-admin role assignments to trusted users only and monitor for unusual storage domain configurations. Review role permissions and consider limiting the ability to set VM.other_config parameters to higher privileged roles if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- XEN
- Date Reserved
- 2026-01-14T13:07:36.961Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4fbf4868715ace439fdd92
Added to database: 07/09/2026, 15:33:28 UTC
Last enriched: 07/09/2026, 15:48:02 UTC
Last updated: 07/10/2026, 00:22:25 UTC
Views: 9
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