{
  "cveId": "CVE-2026-43404",
  "url": "https://patchblox.com/security/cve/CVE-2026-43404",
  "summary": "CVE-2026-43404 is fixed in 23 products on 1 platform, first by ALAS2023-2026-1596, released April 27, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  mm: Fix a hmm_range_fault() livelock / starvatio...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  mm: Fix a hmm_range_fault() livelock / starvation problem  If hmm_range_fault() fails a folio_trylock() in do_swap_page, trying to acquire the lock of a device-private folio for migration, to ram, the function will spin until it succeeds grabbing the lock.  However, if the process holding the lock is depending on a work item to be completed, which is scheduled on the same CPU as the spinning hmm_range_fault(), that work item might be starved and we end up in a livelock / starvation situation which is never resolved.  This can happen, for example if the process holding the device-private folio lock is stuck in    migrate_device_unmap()-\u003Elru_add_drain_all() sinc lru_add_drain_all() requires a short work-item to be run on all online cpus to complete.  A prerequisite for this to happen is: a) Both zone device and system memory folios are considered in    migrate_device_unmap(), so that there is a reason to call    lru_add_drain_all() for a system memory folio while a    folio lock is held on a zone device folio. b) The zone device folio has an initial mapcount \u003E 1 which causes    at least one migration PTE entry insertion to be deferred to    try_to_migrate(), which can happen after the call to    lru_add_drain_all(). c) No or voluntary only preemption.  This all seems pretty unlikely to happen, but indeed is hit by the \u0022xe_exec_system_allocator\u0022 igt test.  Resolve this by waiting for the folio to be unlocked if the folio_trylock() fails in do_swap_page().  Rename migration_entry_wait_on_locked() to softleaf_entry_wait_unlock() and update its documentation to indicate the new use-case.  Future code improvements might consider moving the lru_add_drain_all() call in migrate_device_unmap() to be called *after* all pages have migration entries inserted. That would eliminate also b) above.  v2: - Instead of a cond_resched() in hmm_range_fault(),   eliminate the problem by waiting for the folio to be unlocked   in do_swap_page() (Alistair Popple, Andrew Morton) v3: - Add a stub migration_entry_wait_on_locked() for the   !CONFIG_MIGRATION case. (Kernel Test Robot) v4: - Rename migrate_entry_wait_on_locked() to   softleaf_entry_wait_on_locked() and update docs (Alistair Popple) v5: - Add a WARN_ON_ONCE() for the !CONFIG_MIGRATION   version of softleaf_entry_wait_on_locked(). - Modify wording around function names in the commit message   (Andrew Morton)  (cherry picked from commit a69d1ab971a624c6f112cea61536569d579c3215)",
  "published": "2026-04-27T09:00:00Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00093,
  "epssPercentile": 0.00551,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "bpftool6.18",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "kernel-livepatch-6.18.20-20.229",
      "release": "amzn 2023",
      "fixedVersion": "1:1.0-0.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
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      "fix": "ALAS2023-2026-1596",
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "product": "linux",
      "release": "Debian 14",
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      "fix": "DEBIAN-CVE-2026-43404",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-43404",
      "released": "2026-05-15T16:01:09Z"
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      "released": "2026-04-27T09:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}