{"id":"CVE-2026-42486","aliases":["ALPINE-CVE-2026-42486","EUVD-2026-42608","GHSA-f6rw-qmp5-m443"],"status":"published","title":"Multiple RBAC issues in XAPI","description":"[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.","severity":{"version":"4.0","score":9.4,"vector":"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","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00167,"percentile":0.06005,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-250"],"published":"2026-07-09T15:16:34Z","modified":"2026-10-25T17:10:00Z","products":[{"vendor":"xapi","product":"xapi"},{"vendor":"xen","product":"xapi"}],"references":[{"url":"https://xenbits.xen.org/xsa/advisory-489.html"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42486"},{"url":"https://github.com/advisories/GHSA-f6rw-qmp5-m443"},{"url":"https://security.alpinelinux.org/vuln/CVE-2026-42486","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-42486","title":"Multiple RBAC issues in XAPI","description":"[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.","status":"published","published":"2026-07-09T15:16:34.88Z","modified":"2026-07-10T03:55:43.73Z","cvss":[{"version":"4.0","score":9.4,"vector":"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","level":"critical","assessor":"cna"}],"cwes":["CWE-250"],"updated_at":"2026-11-02T13:40:23.731501Z"}],"euvd":[{"id":"EUVD-2026-42608","description":"[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.","status":"published","published":"2026-07-09T15:16:34Z","modified":"2026-07-10T03:55:43Z","cvss":[{"version":"4.0","score":9.4,"vector":"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","level":"critical"}],"updated_at":"2026-11-02T18:20:03.742277Z"}],"ghsa":[{"id":"GHSA-f6rw-qmp5-m443","title":"[This CNA information record relates to multiple CVEs; the text explains which aspects...","description":"[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.","status":"published","published":"2026-07-09T18:31:51Z","modified":"2026-07-09T18:31:59Z","cvss":[{"version":"4.0","score":9.4,"vector":"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","level":"critical"}],"cwes":["CWE-250"],"updated_at":"2026-11-02T15:09:22.189239Z"}],"nvd":[{"id":"CVE-2026-42486","description":"[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.","status":"published","published":"2026-07-09T16:16:41.443Z","modified":"2026-10-25T17:10:00.197Z","cvss":[{"version":"4.0","score":9.4,"vector":"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","level":"critical","assessor":"secondary"}],"cwes":["CWE-250"],"updated_at":"2026-11-02T14:12:28.4135Z"}],"osv":[{"id":"ALPINE-CVE-2026-42486","description":"[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.","status":"withdrawn","published":"2026-07-09T16:16:41.443Z","modified":"2026-07-14T08:03:33.287049869Z","cvss":[{"version":"4.0","score":9.4,"vector":"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","level":"critical"}],"updated_at":"2026-11-02T15:27:50.764331Z"}]}}