{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-40051",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-40051"
  ],
  "published": "2025-10-28T11:50:45Z",
  "summary": "vhost: vringh: Modify the return value check",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost: vringh: Modify the return value check\n\nThe return value of copy_from_iter and copy_to_iter can't be negative,\ncheck whether the copied lengths are equal.",
  "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": "6.1.156",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-40051"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/db042925a5ab7a550b710addeadbf6f72e3a8a4b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/78dc7362662fedaa1928fb8e4f27401c8322905d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/baa37b1c7e29546f79c39bef0d18c4edc9f39bb1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cfa0654402c06d086201a9ff167eb95da5844fc3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/82a8d0fda55b35361ee7f35b54fa2b66d7847d2b"
    }
  ],
  "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 vringh IOTLB copy path is driven entirely through local ioctls on the `/dev/vhost-vdpa-N` character device (VHOST_IOTLB_UPDATE, vring setup, kick), with no network-facing consumer. A malicious guest cannot trigger it because it cannot unmap the host-side VA backing, so the attacker must be a local process.\nAC:L - The attacker deterministically forces the short copy by registering an IOTLB mapping over a shared file mapping and then truncating/unmapping it, so `copy_from_user` faults at a chosen offset every time \u2014 no race or unpredictable state is involved. The stale-stack values feeding `hdr.sector` and `struct vring_desc` are groomable with ordinary syscalls.\nPR:L - `vhost_vdpa_open()` and the vhost-vdpa ioctl handlers contain no `capable()`/`CAP_*` checks, so any user holding the device node can drive the full path, and in standard virtualization deployments that node is granted to an unprivileged VMM process. Only device *creation* needs admin, which is the normal host configuration, not an attacker step.\nUI:N - The attacker performs every step itself \u2014 map, truncate, kick the virtqueue \u2014 within its own process. No victim action or interaction is required.\nS:U - The corruption and disclosure occur in the host kernel that already governs the attacking process; this is standard local kernel compromise. No IOMMU, VM, or sandbox authority boundary is crossed by the bug itself.\nC:H - A silently-swallowed short pull causes `vdpasim_net_work()` to push a full PAGE_SIZE of the non-zeroed `kvmalloc` buffer `net->buffer` into the attacker's RX ring, directly disclosing stale kernel heap. Additionally the uninitialized `hdr.sector` drives `vringh_iov_push_iotlb(..., blk->buffer + offset, ...)` past the wrapped `VDPASIM_BLK_CAPACITY - start_sector` guard, giving an out-of-bounds kernel heap read echoed back to the attacker.\nI:H - In `vdpasim_blk_handle_req()` the uninitialized stack `hdr.sector` becomes the destination offset for `vringh_iov_pull_iotlb(..., blk->buffer + (sector << SECTOR_SHIFT), to_pull)`, an out-of-bounds kernel heap write of attacker-supplied data at a groomable offset. `__vringh_iov()` likewise builds iov entries whose `iov_base`/`iov_len` come from uninitialized kernel stack, giving further attacker-influenced memory corruption.\nA:H - Descriptors and request headers fabricated from uninitialized kernel stack yield bogus IOVAs and lengths up to 4 GB, and the resulting out-of-bounds heap accesses and invalid `pfn_to_page()`/page translations cause kernel oops or panic. The condition is repeatable at will from a single unprivileged process."
    }
  }
}