{
  "cveId": "CVE-2026-89758",
  "url": "https://patchblox.com/security/cve/CVE-2026-89758",
  "summary": "CVE-2026-89758 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89758 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  mm/mempolicy: skip non-present PMDs when queuein...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  mm/mempolicy: skip non-present PMDs when queueing folios  Patch series \u0022mm: handle device-private PMDs in walk callbacks\u0022, v3.  Since commit 368076f52ebe (\u0022mm/huge_memory: add device-private THP support to PMD operations\u0022) a PMD may hold a device-private swap entry whenever an HMM-based GPU driver migrates an anonymous THP folio to device memory via migrate_vma_pages().  pmd_trans_huge_lock() succeeds for such PMDs (pmd_is_huge() returns true for any non-present, non-none huge PMD), so several MM walk callbacks that used to assume present THP or migration entry are now reachable with a device-private PMD.  The results range from a VM_BUG_ON() firing on debug kernels, to an oops on a bogus vmemmap dereference, to silently isolating an unrelated live folio from LRU in the aliasing case.   This patch (of 3):  queue_folios_pmd() is called under pmd_trans_huge_lock(), whose pmd_is_huge() check returns true for any non-present, non-none PMD softleaf.  Passing such a PMD to pmd_folio() treats the softleaf encoding as a hardware PFN and can return a bogus folio pointer.  Mirror queue_folios_pte_range(): handle non-present entries before looking up a folio.  Keep migration entries counted as failures, but skip other non-present PMDs such as device-private entries.  Potential trigger: an HMM-based GPU driver migrates an anonymous THP folio to device memory via migrate_vma_pages(), leaving a device-private PMD.  Userspace then calls mbind(), migrate_pages() or set_mempolicy_home_node() on that range.",
  "published": "2026-09-11T20:20:06Z",
  "severity": "high",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00165,
  "epssPercentile": 0.05764,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-89758",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89758",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}