CVE-2023-46835 (GCVE-0-2023-46835)
Vulnerability from cvelistv5
Published
2024-01-05 16:34
Modified
2025-11-04 19:25
Summary
The current setup of the quarantine page tables assumes that the quarantine domain (dom_io) has been initialized with an address width of DEFAULT_DOMAIN_ADDRESS_WIDTH (48) and hence 4 page table levels. However dom_io being a PV domain gets the AMD-Vi IOMMU page tables levels based on the maximum (hot pluggable) RAM address, and hence on systems with no RAM above the 512GB mark only 3 page-table levels are configured in the IOMMU. On systems without RAM above the 512GB boundary amd_iommu_quarantine_init() will setup page tables for the scratch page with 4 levels, while the IOMMU will be configured to use 3 levels only, resulting in the last page table directory (PDE) effectively becoming a page table entry (PTE), and hence a device in quarantine mode gaining write access to the page destined to be a PDE. Due to this page table level mismatch, the sink page the device gets read/write access to is no longer cleared between device assignment, possibly leading to data leaks.
Impacted products
Show details on NVD website


{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-04T19:25:41.611Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://xenbits.xenproject.org/xsa/advisory-445.html"
          },
          {
            "url": "http://xenbits.xen.org/xsa/advisory-445.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "NONE",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2023-46835",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-04-12T04:00:28.791183Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-787",
                "description": "CWE-787 Out-of-bounds Write",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-06-17T16:11:08.422Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
          "versions": [
            {
              "status": "unknown",
              "version": "consult Xen advisory XSA-445"
            }
          ]
        }
      ],
      "configurations": [
        {
          "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"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Roger Pau Monn\u00e9 of XenServer.\n"
        }
      ],
      "datePublic": "2023-11-14T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "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"
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "A device in quarantine mode can access data from previous quarantine\npage table usages, possibly leaking data used by previous domains that\nalso had the device assigned.\n"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2024-01-05T16:34:49.531Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
      },
      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-445.html"
        }
      ],
      "title": "x86/AMD: mismatch in IOMMU quarantine page table levels",
      "workarounds": [
        {
          "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"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2023-46835",
    "datePublished": "2024-01-05T16:34:49.531Z",
    "dateReserved": "2023-10-27T07:55:35.331Z",
    "dateUpdated": "2025-11-04T19:25:41.611Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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