ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page

{
  "id": "337816eaaa4e09b6b9445426d4a160811ae733662cb7b243180ca5b7d008a1d8",
  "url": "https://osv.dev/vulnerability/CVE-2026-89500",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page Discarding a cached reader page after a concurrent ring buffer resize uses the new global subbuf_order for the free_pages() call. This mismatched order may crashes the kernel or leaks memory because the cached page was allocated under the old size. Save the actual free_page order alongside the page address to ensure we always refer to the correct value and do not rely on the potentially stalled cpu_buffer->subbuf_order value. The simplest is to make free_page a buffer_data_read_page which already covers exactly what we need: a page address and a page order.",
    "evidence": "osv:CVE-2026-89500",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.112",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.51",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-89500",
      "aliases": [
        "CVE-2026-89500"
      ],
      "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": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "7a1fb95de5404134f8758c1295ce88986bdf117c"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89500.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.8.0"
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                {
                  "fixed": "6.12.112"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.51"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.4"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89500.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.225690400Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/7a1fb95de5404134f8758c1295ce88986bdf117c",
        "https://git.kernel.org/stable/c/a1dabe68fb53730bc0be60c5dbfd3f4c560084e7",
        "https://git.kernel.org/stable/c/d787d509bdf6c88c85e095247daf7456cb7fb772",
        "https://git.kernel.org/stable/c/d8f52dc3c3f1f987d8cf920ccd8d66590870bf3f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89500.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89500",
        "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-2026-89500.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89500",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497305,
  "published_at": "2026-09-11T19:43:49.392+00:00"
}