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CWE-250Weakness · CWE-250

CVE-2026-23560

CRITICAL · 9.4 CVSS v4.0 Published 2026-07-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
99/100
Remediation priority · Urgent
No privileges Zero-click 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
[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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vm-admin (lower-privileged role) can set VM.other-config:is_system_domain to mark a VM as a system domain, bypassing intended RBAC restrictions that should limit this to pool-admin. System domains are treated specially by XAPI - they are ignored during certain host/pool operations and may be hidden from tooling, allowing a vm-admin to effectively circumvent normal VM lifecycle controls and potentially evade administrative oversight.

MitigationRestrict setting of VM.other-config:is_system_domain to pool-admin role only by adding proper authorization checks in the XAPI code path that handles this parameter. Verify all other sensitive VM.other-config and VM.platform parameters have appropriate role restrictions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify XAPI is present in the environment
    Identify if XenServer or Citrix Hypervisor is installed by checking for the XAPI daemon process (xe daemon) or by attempting to connect to the XenAPI endpoint (typically port 443 on the host)
    Affected if XAPI is not present, the environment is not affected by this specific vulnerability in XAPI
  2. Identify VMs with is_system_domain configured
    Query XAPI for VMs that have the key 'is_system_domain' set in their other-config metadata. Use xe vm-list other-config:is_system_domain=true or query the XenAPI directly for VM objects with this key present
    Affected if No VMs have is_system_domain set in other-config, the environment is not currently vulnerable to this specific exploitation vector
  3. Check RBAC role assignments for vm-admin users
    Review the RBAC (Role-Based Access Control) configuration to identify users or subjects assigned the vm-admin role. Query XAPI's RBAC data using xe subject-list and xe role-list, or inspect the internal RBAC database
    Affected if Only pool-admin roles exist or no vm-admin users exist, the privilege escalation aspect of this vulnerability cannot be exploited
  4. Confirm which roles can currently modify VM.other-config:is_system_domain
    Attempt to set is_system_domain using an account with vm-admin role privileges (non-pool-admin). If the operation succeeds without authorization failure, the vulnerability is present
    Affected if vm-admin role successfully sets is_system_domain, the environment is affected by the authorization bypass described in this CVE

A user is affected if XAPI is present, a vm-admin role user can successfully set VM.other-config:is_system_domain on any VM, allowing them to elevate privileges by marking VMs as system domains.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict setting of VM.other-config:is_system_domain to pool-admin role only by adding proper authorization checks in the XAPI code path that handles this parameter. Verify all other sensitive VM.other-config and VM.platform parameters have appropriate role restrictions.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23560 in production — separate from our analysis above.

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