CVE-2026-23562: 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 roles have limited permissions. CVE-2026-23562 arises because one API related to PCI passthrough configuration lacks the proper role check, enabling a vm-admin to access host hardware resources that should be restricted to pool-admins. This improper privilege enforcement constitutes a CWE-250 (Execution with Unnecessary Privileges) vulnerability. The CVSS 4.0 score is 9.4 (critical), reflecting the high impact of unauthorized hardware access. This issue is one among multiple related vulnerabilities in XAPI affecting role-based restrictions.
Potential Impact
A vm-admin user can configure PCI passthrough settings that should be limited to the pool-admin role, potentially gaining unauthorized access to host hardware. This could lead to unauthorized control or manipulation of hardware resources, increasing the risk of privilege escalation or system compromise within the Xen environment.
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 activity related to PCI passthrough configuration. Review role assignments and consider limiting the number of users with vm-admin privileges.
CVE-2026-23562: 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 roles have limited permissions. CVE-2026-23562 arises because one API related to PCI passthrough configuration lacks the proper role check, enabling a vm-admin to access host hardware resources that should be restricted to pool-admins. This improper privilege enforcement constitutes a CWE-250 (Execution with Unnecessary Privileges) vulnerability. The CVSS 4.0 score is 9.4 (critical), reflecting the high impact of unauthorized hardware access. This issue is one among multiple related vulnerabilities in XAPI affecting role-based restrictions.
Potential Impact
A vm-admin user can configure PCI passthrough settings that should be limited to the pool-admin role, potentially gaining unauthorized access to host hardware. This could lead to unauthorized control or manipulation of hardware resources, increasing the risk of privilege escalation or system compromise within the Xen environment.
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 activity related to PCI passthrough configuration. Review role assignments and consider limiting the number of users with vm-admin privileges.
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: 6a4fbf4868715ace439fdd95
Added to database: 07/09/2026, 15:33:28 UTC
Last enriched: 07/09/2026, 15:47:55 UTC
Last updated: 07/10/2026, 00:08:03 UTC
Views: 11
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