CVE-2026-98002 (GCVE-0-2026-98002)
Vulnerability from cvelistv5
Published
2026-09-25 10:23
Modified
2026-10-19 09:12
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: iommu/amd: Fix ineffective error check in nested domain allocation amd_iommu_pdom_id_alloc() returns an int: a domain ID on success, or the negative errno from ida_alloc_range() when the ID space is exhausted or memory is short. amd_iommu_alloc_domain_nested() stores that return value in gdom_info->hdom_id, which is a u32, and only then tests it: gdom_info->hdom_id = amd_iommu_pdom_id_alloc(); if (gdom_info->hdom_id <= 0) { The assignment discards the sign, so -ENOSPC becomes 0xffffffe4 and the test never fires. The nested domain is then set up with a host domain ID that was never allocated, instead of the allocation failing with -ENOSPC. Keep the value in an int, test it there, and store it only once it is known to be valid, which is what the other amd_iommu_pdom_id_alloc() callers already do.
References
Impacted products
Vendor Product Version
Linux Linux Version: 757d2b1fdf5b7d6eead5963a49b5780617987ab8
Version: 757d2b1fdf5b7d6eead5963a49b5780617987ab8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/amd/nested.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "80c231f5577229d1e90a1e312b3095f9502f8625",
              "status": "affected",
              "version": "757d2b1fdf5b7d6eead5963a49b5780617987ab8",
              "versionType": "git"
            },
            {
              "lessThan": "fa5c0827f0b7bac6d0a188f10118151769ae68fd",
              "status": "affected",
              "version": "757d2b1fdf5b7d6eead5963a49b5780617987ab8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/amd/nested.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd: Fix ineffective error check in nested domain allocation\n\namd_iommu_pdom_id_alloc() returns an int: a domain ID on success, or the\nnegative errno from ida_alloc_range() when the ID space is exhausted or\nmemory is short.  amd_iommu_alloc_domain_nested() stores that return value\nin gdom_info-\u003ehdom_id, which is a u32, and only then tests it:\n\n\tgdom_info-\u003ehdom_id = amd_iommu_pdom_id_alloc();\n\tif (gdom_info-\u003ehdom_id \u003c= 0) {\n\nThe assignment discards the sign, so -ENOSPC becomes 0xffffffe4 and the\ntest never fires.  The nested domain is then set up with a host domain ID\nthat was never allocated, instead of the allocation failing with -ENOSPC.\n\nKeep the value in an int, test it there, and store it only once it is\nknown to be valid, which is what the other amd_iommu_pdom_id_alloc()\ncallers already do."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The patched function amd_iommu_alloc_domain_nested() is reached only via the IOMMU_HWPT_ALLOC ioctl on a local iommufd fd (/dev/iommu) against an AMD vIOMMU (iommufd_hwpt_alloc -\u003e viommu-\u003eops-\u003ealloc_domain_nested); no remote protocol carries the input.\nAC:H - The failure path needs ida_alloc_range() in amd_iommu_pdom_id_alloc() to fail: either all 65535 global host domain IDs are in use with a victim domain holding 0xffe4, which lowest-first allocation doesn\u0027t let the attacker arrange on demand, or a GFP_ATOMIC failure the attacker cannot force.\nPR:L - Needs a VMM-style user that has been given /dev/iommu (0660) and a bound VFIO device cdev to create a vIOMMU and nested HWPTs; that is delegated device access, not full init-namespace root.\nUI:N - The attacker allocates the nested HWPTs and attaches the device themselves; nobody else has to do anything.\nS:C - The unallocated hdom_id (truncated to 0xffe4/0xfff4 by DTE_DOMID_MASK) is written into the DTE by set_dte_nested(), so the nested device shares IOTLB tags with another IOMMU domain, breaking the DMA isolation boundary between domains.\nC:H - Because the DomID is aliased, the device\u0027s DMA can hit IOTLB translations cached for the other domain and read memory belonging to that domain.\nI:H - The same aliased IOTLB entries let the device\u0027s DMA writes land in the other domain\u0027s pages, corrupting memory outside the nested domain.\nA:H - Stray DMA writes into another domain\u0027s memory, plus invalidations for the parent S2 hitting the shared hdom_id, can corrupt host or guest memory used by other devices and bring them down."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:12:07.970Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/80c231f5577229d1e90a1e312b3095f9502f8625"
        },
        {
          "url": "https://git.kernel.org/stable/c/fa5c0827f0b7bac6d0a188f10118151769ae68fd"
        }
      ],
      "title": "iommu/amd: Fix ineffective error check in nested domain allocation",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98002",
    "datePublished": "2026-09-25T10:23:29.929Z",
    "dateReserved": "2026-09-25T10:19:56.068Z",
    "dateUpdated": "2026-10-19T09:12:07.970Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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