{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2023-46835",
        "ASSIGNER": "security@xen.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "The current setup of the quarantine page tables assumes that the\nquarantine domain (dom_io) has been initialized with an address width\nof DEFAULT_DOMAIN_ADDRESS_WIDTH (48) and hence 4 page table levels.\n\nHowever dom_io being a PV domain gets the AMD-Vi IOMMU page tables\nlevels based on the maximum (hot pluggable) RAM address, and hence on\nsystems with no RAM above the 512GB mark only 3 page-table levels are\nconfigured in the IOMMU.\n\nOn systems without RAM above the 512GB boundary\namd_iommu_quarantine_init() will setup page tables for the scratch\npage with 4 levels, while the IOMMU will be configured to use 3 levels\nonly, resulting in the last page table directory (PDE) effectively\nbecoming a page table entry (PTE), and hence a device in quarantine\nmode gaining write access to the page destined to be a PDE.\n\nDue to this page table level mismatch, the sink page the device gets\nread/write access to is no longer cleared between device assignment,\npossibly leading to data leaks.\n"
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Xen",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Xen",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "status": "unknown",
                                                        "version": "consult Xen advisory XSA-445"
                                                    }
                                                ],
                                                "defaultStatus": "unknown"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://xenbits.xenproject.org/xsa/advisory-445.html",
                "refsource": "MISC",
                "name": "https://xenbits.xenproject.org/xsa/advisory-445.html"
            }
        ]
    },
    "configuration": [
        {
            "lang": "en",
            "value": "All Xen versions supporting PCI passthrough are affected.\n\nOnly x86 AMD systems with IOMMU hardware are vulnerable.\n\nOnly x86 guests which have physical devices passed through to them can\nleverage the vulnerability.\n"
        }
    ],
    "work_around": [
        {
            "lang": "en",
            "value": "Not passing through physical devices to guests will avoid the\nvulnerability.\n\nNot using quarantine scratch-page mode will avoid the vulnerability,\nbut could result in other issues.\n"
        }
    ],
    "credits": [
        {
            "lang": "en",
            "value": "This issue was discovered by Roger Pau Monn\u00e9 of XenServer.\n"
        }
    ]
}