CVE-2026-43303 (GCVE-0-2026-43303)
Vulnerability from cvelistv5
Published
2026-05-08 13:11
Modified
2026-08-05 12:27
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: clear page->private in free_pages_prepare() Several subsystems (slub, shmem, ttm, etc.) use page->private but don't clear it before freeing pages. When these pages are later allocated as high-order pages and split via split_page(), tail pages retain stale page->private values. This causes a use-after-free in the swap subsystem. The swap code uses page->private to track swap count continuations, assuming freshly allocated pages have page->private == 0. When stale values are present, swap_count_continued() incorrectly assumes the continuation list is valid and iterates over uninitialized page->lru containing LIST_POISON values, causing a crash: KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107] RIP: 0010:__do_sys_swapoff+0x1151/0x1860 Fix this by clearing page->private in free_pages_prepare(), ensuring all freed pages have clean state regardless of previous use.
References
Impacted products
Vendor Product Version
Linux Linux Version: 3b8000ae185cb068adbda5f966a3835053c85fd4
Version: 3b8000ae185cb068adbda5f966a3835053c85fd4
Version: 3b8000ae185cb068adbda5f966a3835053c85fd4
Version: 3b8000ae185cb068adbda5f966a3835053c85fd4
Version: 3b8000ae185cb068adbda5f966a3835053c85fd4
Version: 3b8000ae185cb068adbda5f966a3835053c85fd4
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{
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          "programFiles": [
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: clear page-\u003eprivate in free_pages_prepare()\n\nSeveral subsystems (slub, shmem, ttm, etc.) use page-\u003eprivate but don\u0027t\nclear it before freeing pages.  When these pages are later allocated as\nhigh-order pages and split via split_page(), tail pages retain stale\npage-\u003eprivate values.\n\nThis causes a use-after-free in the swap subsystem.  The swap code uses\npage-\u003eprivate to track swap count continuations, assuming freshly\nallocated pages have page-\u003eprivate == 0.  When stale values are present,\nswap_count_continued() incorrectly assumes the continuation list is valid\nand iterates over uninitialized page-\u003elru containing LIST_POISON values,\ncausing a crash:\n\n  KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]\n  RIP: 0010:__do_sys_swapoff+0x1151/0x1860\n\nFix this by clearing page-\u003eprivate in free_pages_prepare(), ensuring all\nfreed pages have clean state regardless of previous use."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable swap continuation and page allocator paths are reached through local memory-management activity such as fork/swap/reclaim or swap administration, not by remote packets or physical access.\nAC:L - There is no attacker-uncontrolled race; a local attacker can repeatedly create swap pressure and duplicate swapped entries to drive the continuation path, and allocator grooming is under attacker influence.\nPR:L - Although swapon/swapoff require CAP_SYS_ADMIN in init_user_ns, the same vulnerable swap_count_continued() path is reachable by an unprivileged local user through normal swapped PTE duplication paths once swap is active.\nUI:N - No victim action is required after the attacker has local execution; the trigger can be driven by the attacker\u0027s own processes and memory activity.\nS:U - The impact remains within the kernel and the same host security authority; this is not a VM escape or cross-boundary IOMMU/DMA issue.\nC:H - The stale page-\u003eprivate value causes a use-after-free style interpretation of stale struct page list metadata, leading to wild kernel memory accesses that can plausibly be shaped into information disclosure.\nI:H - swap_count_continued() can write through a page derived from stale list pointers, making this kernel memory corruption with plausible arbitrary write/control-flow impact.\nA:H - The reported failure is a KASAN wild-memory-access crash in __do_sys_swapoff, and the same invalid list traversal can oops or panic the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:27:08.856Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e7790ab165713b79b1617ce659742ceb3a859d05"
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        {
          "url": "https://git.kernel.org/stable/c/3edb8ebbf79b9016040e8f3421d723ae3d542b32"
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          "url": "https://git.kernel.org/stable/c/23b82b7a26182ad840ae67d390d7ec9771e8c00f"
        },
        {
          "url": "https://git.kernel.org/stable/c/d757c793853ec5483eb41ec2942c300b8fa720fb"
        },
        {
          "url": "https://git.kernel.org/stable/c/ac1ea219590c09572ed5992dc233bbf7bb70fef9"
        }
      ],
      "title": "mm/page_alloc: clear page-\u003eprivate in free_pages_prepare()",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43303",
    "datePublished": "2026-05-08T13:11:23.561Z",
    "dateReserved": "2026-05-01T14:12:56.000Z",
    "dateUpdated": "2026-08-05T12:27:08.856Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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