arm64: Reserve an extra page for early kernel mapping

{
  "id": "e4f14ce37eca8387635e62ca7eb024615eaf5d811593b5ea73505d075430691e",
  "url": "https://osv.dev/vulnerability/CVE-2026-53288",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "arm64: Reserve an extra page for early kernel mapping",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: arm64: Reserve an extra page for early kernel mapping The final part of [data, end) segment may overflow into the next page of init_pg_end[1] which is the gap page before early_init_stack[2]: [1] crash_arm64_v9.0.1> vtop ffffffed00601000 VIRTUAL PHYSICAL ffffffed00601000 83401000 PAGE DIRECTORY: ffffffecffd62000 PGD: ffffffecffd62da0 => 10000000833fb003 PMD: ffffff80033fb018 => 10000000833fe003 PTE: ffffff80033fe008 => 68000083401f03 PAGE: 83401000 PTE PHYSICAL FLAGS 68000083401f03 83401000 (VALID|SHARED|AF|NG|PXN|UXN) PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffffec00d0040 83401000 0 0 1 4000 reserved [2] ffffffed002c8000 (r) __pi__data ffffffed0054e000 (d) __pi___bss_start ffffffed005f5000 (b) __pi_init_pg_dir ffffffed005fe000 (b) __pi_init_pg_end ffffffed005ff000 (B) early_init_stack ffffffed00608000 (b) __pi__end For 4K pages, the early kernel mapping may use 2MB block entries but the kernel segments are only 64KB aligned. Segment boundaries that fall within a 2MB block therefore require a PTE table so that different attributes can be applied on either side of the boundary. KERNEL_SEGMENT_COUNT still correctly counts the five permanent kernel VMAs registered by declare_kernel_vmas(). However, since commit 5973a62efa34 (\"arm64: map [_text, _stext) virtual address range non-executable+read-only\"), the early mapper also maps [_text, _stext) separately from [_stext, _etext). This adds one more early-only split",
    "evidence": "osv:CVE-2026-53288",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.91",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.33",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-53288",
      "aliases": [
        "CVE-2026-53288"
      ],
      "affected": [
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53288.json"
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        {
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:46.502922948Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/4d8e74ad4585672489da6145b3328d415f50db82",
        "https://git.kernel.org/stable/c/9fe9e3acaa14921b0cf0d6cc2de5b562499bf721",
        "https://git.kernel.org/stable/c/a4ff33053da0a34b14abb5c96dc5a48379e26fce",
        "https://git.kernel.org/stable/c/dcb89deed40ba55ff7020061712fdabf098cc2cc",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53288.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-53288",
        "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/2026/53xxx/CVE-2026-53288.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-53288",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 514458,
  "published_at": "2026-06-26T19:40:48.528+00:00"
}