ACPI: pfr_update: fix stack buffer overflow in query_capability()

{
  "id": "b105e151fe3589a83d061a1a124db950cf47134799732505672a9b1d490af317",
  "url": "https://osv.dev/vulnerability/CVE-2026-89587",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ACPI: pfr_update: fix stack buffer overflow in query_capability()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ACPI: pfr_update: fix stack buffer overflow in query_capability() query_capability() copies four ACPI buffer objects returned by the firmware _DSM into fixed-size u8[16] fields in struct pfru_update_cap_info using memcpy with the firmware-supplied length: memcpy(&cap_hdr->code_type, elements[CAP_CODE_TYPE_IDX].buffer.pointer, elements[CAP_CODE_TYPE_IDX].buffer.length); The same pattern repeats for drv_type, platform_id, and oem_id. If the firmware returns buffer.length > 16 for any of these fields, memcpy writes past the destination array. struct pfru_update_cap_info is stack-allocated in pfru_ioctl(). Confirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports are generated when a DSM returns 64-byte buffers, with writes reaching 44 bytes past the end of cap_hdr's [64, 156) frame window into adjacent stack redzones. Introduce a helper pointer to out_obj->package.elements and use it to validate each buffer length against its destination field size before copying, returning -EINVAL if the firmware supplies an oversized buffer.",
    "evidence": "osv:CVE-2026-89587",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
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            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.109",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.50",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-89587",
      "aliases": [
        "CVE-2026-89587"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
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          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
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                  "fixed": "c5a31b4e7e37c92550be9a2edf51ca853a4d251a"
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                {
                  "fixed": "a2151624b55029dad0ca7efd17fb83a0461c8843"
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                {
                  "fixed": "6d4ed2fd022bc862b156e53aae163b61259e1caa"
                },
                {
                  "fixed": "15d2b7f38f95d28652170344f39ee492c55e567c"
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                {
                  "fixed": "ced45be0073a8a31b30b4a7f68cd3a15734515de"
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          "database_specific": {
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              "type": "ECOSYSTEM",
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                  "introduced": "6.19.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89587.json"
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      ],
      "modified": "2026-10-28T02:30:39.402580683Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/15d2b7f38f95d28652170344f39ee492c55e567c",
        "https://git.kernel.org/stable/c/6d4ed2fd022bc862b156e53aae163b61259e1caa",
        "https://git.kernel.org/stable/c/a2151624b55029dad0ca7efd17fb83a0461c8843",
        "https://git.kernel.org/stable/c/c5a31b4e7e37c92550be9a2edf51ca853a4d251a",
        "https://git.kernel.org/stable/c/ced45be0073a8a31b30b4a7f68cd3a15734515de",
        "https://git.kernel.org/stable/c/d3af83e327565a9444cebc0db714cb837e493046",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89587.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89587",
        "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/2026/89xxx/CVE-2026-89587.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89587",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506865,
  "published_at": "2026-09-11T19:44:52.066+00:00"
}