drivers/base/memory: set mem->altmap after successful device registration

{
  "id": "12823ddc998721dab6944261c824aad133c9da8f03618ac6b74c6a0e09d3f1c8",
  "url": "https://osv.dev/vulnerability/CVE-2026-64244",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drivers/base/memory: set mem->altmap after successful device registration",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: drivers/base/memory: set mem->altmap after successful device registration If __add_memory_block() fails at xa_store() (under memory pressure for example), device_unregister() is called, which eventually triggers memory_block_release() with mem->altmap still set, causing a WARN_ON(mem->altmap). This was triggered by modifying virtio-mem driver. Fix this by delaying the assignment of mem->altmap until after __add_memory_block() has succeeded.",
    "evidence": "osv:CVE-2026-64244",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.144",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.95",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.37",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.14",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-64244",
      "aliases": [
        "CVE-2026-64244"
      ],
      "affected": [
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                  "fixed": "22dc0d042f02ce82aa61422ea5f232628bfd9e9c"
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                  "fixed": "bc3dd82a0ffd488bb902f4c69c3d28fd4088d973"
                },
                {
                  "fixed": "059ac6252a63edf1cea79bf30bd860a8c264b62c"
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                {
                  "fixed": "a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a"
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              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64244.json"
          }
        },
        {
          "ranges": [
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              "type": "ECOSYSTEM",
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                  "introduced": "6.6.0"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64244.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.970103762Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/059ac6252a63edf1cea79bf30bd860a8c264b62c",
        "https://git.kernel.org/stable/c/22dc0d042f02ce82aa61422ea5f232628bfd9e9c",
        "https://git.kernel.org/stable/c/6c25bf4e44a2b6a14332f952bba0974521f5b72d",
        "https://git.kernel.org/stable/c/802e113cf120df7208e4c7e604950a85e87120a8",
        "https://git.kernel.org/stable/c/a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a",
        "https://git.kernel.org/stable/c/bc3dd82a0ffd488bb902f4c69c3d28fd4088d973",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64244.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64244",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64244.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64244",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 509276,
  "published_at": "2026-07-24T15:29:59.891+00:00"
}