{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-37949",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2025-37949"
  ],
  "published": "2025-05-20T16:02:18Z",
  "summary": "xenbus: Use kref to track req lifetime",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxenbus: Use kref to track req lifetime\n\nMarek reported seeing a NULL pointer fault in the xenbus_thread\ncallstack:\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nRIP: e030:__wake_up_common+0x4c/0x180\nCall Trace:\n <TASK>\n __wake_up_common_lock+0x82/0xd0\n process_msg+0x18e/0x2f0\n xenbus_thread+0x165/0x1c0\n\nprocess_msg+0x18e is req->cb(req).  req->cb is set to xs_wake_up(), a\nthin wrapper around wake_up(), or xenbus_dev_queue_reply().  It seems\nlike it was xs_wake_up() in this case.\n\nIt seems like req may have woken up the xs_wait_for_reply(), which\nkfree()ed the req.  When xenbus_thread resumes, it faults on the zero-ed\ndata.\n\nLinux Device Drivers 2nd edition states:\n\"Normally, a wake_up call can cause an immediate reschedule to happen,\nmeaning that other processes might run before wake_up returns.\"\n... which would match the behaviour observed.\n\nChange to keeping two krefs on each request.  One for the caller, and\none for xenbus_thread.  Each will kref_put() when finished, and the last\nwill free it.\n\nThis use of kref matches the description in\nDocumentation/core-api/kref.rst",
  "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": "6.1.139",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-37949"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0e94a246bb6d9538010b6c02d2b1d4717a97b2e5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f1bcac367bc95631afbb918348f30dec887d0e1b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4d260a5558df4650eb87bc41b2c9ac2d6b2ba447"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8b02f85e84dc6f7c150cef40ddb69af5a25659e5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cbfaf46b88a4c01b64c4186cdccd766c19ae644c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8e9c8a0393b5f85f1820c565ab8105660f4e8f92"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2466b0f66795c3c426cacc8998499f38031dbb59"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z"
  }
}