{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-39951",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-39951"
  ],
  "published": "2025-10-04T07:33:57Z",
  "summary": "um: virtio_uml: Fix use-after-free after put_device in probe",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\num: virtio_uml: Fix use-after-free after put_device in probe\n\nWhen register_virtio_device() fails in virtio_uml_probe(),\nthe code sets vu_dev->registered = 1 even though\nthe device was not successfully registered.\nThis can lead to use-after-free or other issues.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "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": "6.1.154",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-39951"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/14c231959a16ca41bfdcaede72483362a8c645d7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5e94e44c9cb30d7a383d8ac227f24a8c9326b770"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/aaf900a83508c8cd5cdf765e7749f9076196ec7f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4f364023ddcfe83f7073b973a9cb98584b7f2a46"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/00e98b5a69034b251bb36dc6e7123d7648e218e4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c2ff91255e0157b356cff115d8dc3eeb5162edf2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7ebf70cf181651fe3f2e44e95e7e5073d594c9c0"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable code is a UML platform/virtio driver probe path reached through local device configuration (kernel command line, devicetree, mconsole, or sysfs driver bind), not through any remote protocol; the vhost-user peer is a local UNIX socket. No network-supplied data influences the failing call.\nAC:L - The `register_virtio_device()` failure can be produced deterministically via the OF path (`virtio_device_of_init()` returns -EINVAL when the parent node has more than one available child) and can also be induced by attacker-driven memory pressure on the `ida_alloc`/`dev_set_name`/`device_add` allocations; no condition outside the attacker's influence must hold.\nPR:L - A local unprivileged account on the UML instance suffices to drive the allocation-failure condition that makes the probe fail, and the resulting write-after-free happens with no further authorization check; no capability is validated in `virtio_uml_probe()` itself.\nUI:N - The faulty path executes automatically during driver probe/bind; nothing requires a victim to open a file, mount a filesystem, or otherwise interact.\nS:U - The corrupted memory and the vulnerable code are both in the kernel's own heap and security authority; there is no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The use-after-free leaves a freed `struct virtio_uml_device` (and a dangling `platform_set_drvdata` pointer) in play; an attacker who reclaims the slab slot with a chosen object gains a read primitive over kernel memory contents.\nI:H - The code performs an out-of-lifetime read-modify-write into the freed object, so heap grooming lets an attacker corrupt an unrelated reclaimed kernel structure, which is exploitable toward arbitrary write and control-flow hijack.\nA:H - Writing into freed slab memory corrupts allocator state and adjacent live objects, reliably producing kernel oops/panic (and KASAN slab-use-after-free splats) that take down the kernel instance."
    }
  }
}