CVE-2026-43303 (GCVE-0-2026-43303)

Vulnerability from cvelistv5 – Published: 2026-05-08 13:11 – Updated: 2026-05-08 13:11
VLAI?
Title
mm/page_alloc: clear page->private in free_pages_prepare()
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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 3b8000ae185cb068adbda5f966a3835053c85fd4 , < 23b82b7a26182ad840ae67d390d7ec9771e8c00f (git)
Affected: 3b8000ae185cb068adbda5f966a3835053c85fd4 , < d757c793853ec5483eb41ec2942c300b8fa720fb (git)
Affected: 3b8000ae185cb068adbda5f966a3835053c85fd4 , < ac1ea219590c09572ed5992dc233bbf7bb70fef9 (git)
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    Linux Linux Affected: 5.18
Unaffected: 0 , < 5.18 (semver)
Unaffected: 6.18.16 , ≤ 6.18.* (semver)
Unaffected: 6.19.6 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/page_alloc.c"
          ],
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              "versionType": "semver"
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      "cpeApplicability": [
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              "negate": false,
              "operator": "OR"
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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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-08T13:11:23.561Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "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()",
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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": "2026-05-08T13:11:23.561Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43303\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-08T14:16:37.583\",\"lastModified\":\"2026-05-08T14:16:37.583\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"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\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/23b82b7a26182ad840ae67d390d7ec9771e8c00f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ac1ea219590c09572ed5992dc233bbf7bb70fef9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d757c793853ec5483eb41ec2942c300b8fa720fb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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