{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64514",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-64514"
  ],
  "published": "2026-07-25T08:51:45Z",
  "summary": "userfaultfd: gate must_wait writability check on pte_present()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nuserfaultfd: gate must_wait writability check on pte_present()\n\nuserfaultfd_must_wait() and userfaultfd_huge_must_wait() read the PTE\nwithout taking the page table lock and then apply pte_write() /\nhuge_pte_write() to it.  Those accessors decode bits from the present\nencoding only; on a swap or migration entry they read the offset bits that\nhappen to share the same position and return an undefined result.\n\nThe intent of the check is \"is this fault still WP-blocked?\".  A\nnon-marker swap entry means the page is in transit -- the userfault\ncontext the original fault delivered against is no longer the same, and\nthe swap-in or migration completion path will re-deliver a fresh fault if\nuserspace still needs to handle it.  Worst case under the current code the\ngarbage write bit says \"wait\", and the thread stays asleep until a\nUFFDIO_WAKE that may never arrive.\n\nGate the writability check on pte_present() so the lockless re-check only\ninspects present-PTE bits when the entry is actually present.  The\nnon-present, non-marker case returns \"don't wait\" and lets the fault path\nretry.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.178",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64514"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a5700a4c1c9099ac2ac73fe8a09cf059972e0d2f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d4026417e8184d13850a0bad4d96ceb6ed9f7152"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/29e6f952c5fb7dc1d6b90fe5b7f36063d44ddae0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5f4dbdb0a87596214076b20b94f2b71b522170b3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a6e9a4939e359599701b1da351e84f72e021443a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/60d696a037eeeedfb57756dfe7ec08a1587c8631"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/710183888174639a15fcec16cd1af766b8480bb7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8e80af52db652fbc41320eee45a4f73bc029faf2"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-17T05:24:08Z"
  }
}