{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "7a4ee419e8c144b747a8915856e91a034d7c8f34"
            },
            {
              "fixed": "488d2c76bd9f78433a70690d1054bfae3d39a407"
            },
            {
              "fixed": "62f9dfbf1aceae88b03c5ca08f7d36e943939dec"
            },
            {
              "fixed": "8dfd3d8d74435344ee8dc9237596959c8b2a6cbe"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.17.0"
            },
            {
              "fixed": "6.18.34"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64186.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd: Remove latent out-of-bounds access in IOMMU debugfs\n\nIn iommu_mmio_write() and iommu_capability_write(), the variables\ndbg_mmio_offset and dbg_cap_offset are declared as int. However, they\nare populated using kstrtou32_from_user(). If a user provides a\nsufficiently large value, it can become a negative integer.\n\nPrior to this patch, the AMD IOMMU debugfs implementation was already\nprotected by different mechanisms.\n\n1. #define OFS_IN_SZ 8 ensures the user string \u003c= 8 bytes, so\n   e.g. 0xffffffff isn't a valid input.\n\n  if (cnt \u003e OFS_IN_SZ)\n     return -EINVAL;\n\n2. Implicit type promotion in iommu_mmio_write(), dbg_mmio_offset is int\n   and iommu-\u003emmio_phys_end is u64\n\n  if (dbg_mmio_offset \u003e iommu-\u003emmio_phys_end - sizeof(u64))\n      return -EINVAL;\n\n3. The show handlers would currently catch the negative number and\n   refuse to perform the read.\n\nReplace kstrtou32_from_user() with kstrtos32_from_user() to parse the\ninput, and check for negative values to explicitly prevent out-of-bounds\nmemory accesses directly in iommu_mmio_write() and\niommu_capability_write().",
  "id": "CVE-2026-64186",
  "modified": "2026-08-13T03:51:41.205462798Z",
  "published": "2026-07-19T15:41:08.054Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/488d2c76bd9f78433a70690d1054bfae3d39a407"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/62f9dfbf1aceae88b03c5ca08f7d36e943939dec"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8dfd3d8d74435344ee8dc9237596959c8b2a6cbe"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64186.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64186"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "iommu/amd: Remove latent out-of-bounds access in IOMMU debugfs"
}