CVE-2026-42486

Full vulnerability record from the local CVENow database.

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.

Severity

CRITICAL

CVSS score

9.4 (v4.0)

Vulnerability status

Deferred

Source identifier

[email protected]

Published

2026-07-09 16:16:41.443000

Last modified

2026-10-25 17:10:00.197000

View original CVE JSON

{
  "id": "CVE-2026-42486",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-09T16:16:41.443",
  "lastModified": "2026-10-25T17:10:00.197",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]\nXAPI can configure different users with different roles, using Role\nBased Access Control.  For more details, see:\n\n  https://docs.xenserver.com/en-us/xencenter/current-release/rbac-overview.html#rbac-roles\n\nThe pool-admin role is fully privileged.  Notably, users with this role\ncan also SSH into the host as root.\n\nThe other administrator roles are pool-operator, vm-power-admin and\nvm-admin, each of which are authorised to configure and manage various\naspects of the system.\n\nSome settings are inadequately restricted, and can be set by a lower\nprivilege of administrator than expected.\n\n * CVE-2026-23559: A vm-admin can set VBD.other_config:backend-local and\n   turn arbitrary files in dom0 into VDIs (virtual disks) and give said\n   disks to a VM they control.  This is an arbitrary read and/or modify\n   of files in dom0.\n\n * CVE-2026-23560: A vm-admin can set VM.other-config:is_system_domain\n   and mark a VM as a system domain.  System domains are ignored and\n   left running during certain other host/pool operations, and may be\n   hidden from view in tooling.\n\n * CVE-2026-23561: A vm-admin can set VM.other_config:storage_driver_domain\n   and mark a VM as the storage domain for a particular host storage\n   connection (PBD). Shutting down the VM can cause the PBD to be\n   erroneously marked as unplugged when it is not.\n\n * CVE-2026-23562: Configuration of PCI passthrough is normally\n   restricted to the pool-admin role.  However one API was missing this\n   check, allowing a vm-admin access to unintended host hardware.\n\n * CVE-2026-42486: A vm-admin can set the VM.platform:hvm_serial\n   parameter, which should be restricted to the pool-admin role, as it\n   can allow arbitrary dom0 file write."
    },
    {
      "lang": "es",
      "value": "Este registro de información de la CNA se relaciona con múltiples CVE; el texto explica qué aspectos/vulnerabilidades corresponden a qué CVE.\nXAPI puede configurar diferentes usuarios con diferentes roles, utilizando el control de acceso basado en roles. Para más detalles, consulte:\n\n  https://docs.xenserver.com/en-us/xencenter/current-release/rbac-overview.html#rbac-roles\n\nEl rol pool-admin tiene todos los privilegios. Cabe destacar que los usuarios con este rol también pueden acceder al host por SSH como root.\n\nLos otros roles de administrador son pool-operator, vm-power-admin y vm-admin, cada uno de los cuales está autorizado para configurar y gestionar varios aspectos del sistema.\n\nAlgunas configuraciones están restringidas de forma inadecuada y pueden ser establecidas por un administrador con un privilegio inferior al esperado.\n\n * CVE-2026-23559: Un vm-admin puede establecer VBD.other_config:backend-local y convertir archivos arbitrarios en dom0 en VDIs (discos virtuales) y entregar dichos discos a una VM que controlan. Esto es una lectura y/o modificación arbitraria de archivos en dom0.\n\n * CVE-2026-23560: Un vm-admin puede establecer VM.other-config:is_system_domain y marcar una VM como un dominio de sistema. Los dominios de sistema son ignorados y se mantienen en ejecución durante ciertas otras operaciones de host/pool, y pueden estar ocultos en las herramientas.\n\n * CVE-2026-23561: Un vm-admin puede establecer VM.other_config:storage_driver_domain y marcar una VM como el dominio de almacenamiento para una conexión de almacenamiento de host particular (PBD). Apagar la VM puede hacer que el PBD sea marcado erróneamente como desconectado cuando no lo está.\n\n * CVE-2026-23562: La configuración de PCI passthrough está normalmente restringida al rol pool-admin. Sin embargo, una API carecía de esta verificación, permitiendo a un vm-admin acceder a hardware de host no intencionado.\n\n * CVE-2026-42486: Un vm-admin puede establecer el parámetro VM.platform:hvm_serial, el cual debería estar restringido al rol pool-admin, ya que puede permitir la escritura arbitraria de archivos en dom0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Xen",
          "product": "XAPI",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "all",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "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",
          "baseScore": 9.4,
          "baseSeverity": "CRITICAL",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "HIGH",
          "subIntegrityImpact": "HIGH",
          "subAvailabilityImpact": "HIGH",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-09T00:00:00+00:00",
          "id": "CVE-2026-42486",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-250"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://xenbits.xen.org/xsa/advisory-489.html",
      "source": "[email protected]"
    }
  ]
}