FKIE_CVE-2026-45851

Vulnerability from fkie_nvd - Published: 2026-05-27 14:16 - Updated: 2026-05-27 14:48
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: efi: Fix reservation of unaccepted memory table The reserve_unaccepted() function incorrectly calculates the size of the memblock reservation for the unaccepted memory table. It aligns the size of the table, but fails to account for cases where the table's starting physical address (efi.unaccepted) is not page-aligned. If the table starts at an offset within a page and its end crosses into a subsequent page that the aligned size does not cover, the end of the table will not be reserved. This can lead to the table being overwritten or inaccessible, causing a kernel panic in accept_memory(). This issue was observed when starting Intel TDX VMs with specific memory sizes (e.g., > 64GB). Fix this by calculating the end address first (including the unaligned start) and then aligning it up, ensuring the entire range is covered by the reservation.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0862438c90487e79822d5647f854977d50381505
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9b18bf59977f5c5bc3b11b210520f62500a7adf3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b7bc182ec1846be437351e44164089d988f9d0dd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ba6b6f1502fa55621d1db23f253d54322bdbe4e0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e649b5916725c68f44ebf45fb396df563c5dbaf2
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nefi: Fix reservation of unaccepted memory table\n\nThe reserve_unaccepted() function incorrectly calculates the size of the\nmemblock reservation for the unaccepted memory table. It aligns the\nsize of the table, but fails to account for cases where the table\u0027s\nstarting physical address (efi.unaccepted) is not page-aligned.\n\nIf the table starts at an offset within a page and its end crosses into\na subsequent page that the aligned size does not cover, the end of the\ntable will not be reserved. This can lead to the table being overwritten\nor inaccessible, causing a kernel panic in accept_memory().\n\nThis issue was observed when starting Intel TDX VMs with specific memory\nsizes (e.g., \u003e 64GB).\n\nFix this by calculating the end address first (including the unaligned\nstart) and then aligning it up, ensuring the entire range is covered\nby the reservation."
    }
  ],
  "id": "CVE-2026-45851",
  "lastModified": "2026-05-27T14:48:31.480",
  "metrics": {},
  "published": "2026-05-27T14:16:57.077",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0862438c90487e79822d5647f854977d50381505"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9b18bf59977f5c5bc3b11b210520f62500a7adf3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b7bc182ec1846be437351e44164089d988f9d0dd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ba6b6f1502fa55621d1db23f253d54322bdbe4e0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e649b5916725c68f44ebf45fb396df563c5dbaf2"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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