{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64449",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64449"
  ],
  "published": "2026-07-25T08:51:45Z",
  "summary": "staging: vme_user: bound slave read/write to the kern_buf size",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nstaging: vme_user: bound slave read/write to the kern_buf size\n\nThe SLAVE-path helpers buffer_to_user() and buffer_from_user() copy\n'count' bytes into/out of the fixed-size kern_buf (size_buf ==\nPCI_BUF_SIZE == 0x20000, 128 KiB) using *ppos as the offset, without\nbounding *ppos + count against size_buf.\n\nvme_user_write()/vme_user_read() only clamp count to the VME window size\n(image_size = vme_get_size(resource)), which VME_SET_SLAVE sets from the\nuser-supplied slave.size -- validated against the VME address space (up\nto VME_A32_MAX = 4 GiB), not against PCI_BUF_SIZE.  When the window\nexceeds 128 KiB, a write()/read() copies past the kern_buf allocation.\n\nClamp count against size_buf in both helpers, with an early return when\n*ppos is already at/after the buffer end.  *ppos is >= 0 here (the caller\nrejects negative offsets), so size_buf - *ppos cannot wrap.  This mirrors\nthe existing clamp in the MASTER-path helpers resource_to_user() /\nresource_from_user(), and matches the read()/write() convention of a\nshort transfer at end-of-buffer.\n\nFound by static analysis (CodeQL taint tracking + CBMC bounded model\nchecking) and confirmed dynamically under KASAN with the vme_fake bridge:\n\n  BUG: KASAN: slab-out-of-bounds in _copy_from_user+0x2d/0x80\n  Write of size 262144 at addr ffff888004100000 by task trigger/68\n    _copy_from_user+0x2d/0x80\n    vme_user_write+0x13e/0x240 [vme_user]\n    vfs_write+0x1b8/0x7a0\n    ksys_write+0xb8/0x150",
  "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": "6.1.178",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64449"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/65358d89dc9f1c25d9364b2b3ef0f3b47717f9ed"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/adc8b9c30d716c362646edb45662aa1c641a154a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8eff7cd4817e14dbe3b9952cce55ef52d1d38940"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e99f2df433c63c86c93de1e5f08f16e404388756"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1b495fa0d4927c88d88bf346bf311f2e26e860ed"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9f32f38265014fac7f5dc9490fb01a638ce6e121"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-17T05:24:08Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable path is reached through ioctl(), lseek(), read(), and write() on a local /dev/bus/vme/s* character device. Network or physical VME-bus input is not needed.\nAC:L - The attacker can deterministically configure an aligned slave window larger than 128 KiB and select the copy offset and length; no race or external condition is required. A 256 KiB overflow was dynamically confirmed under KASAN.\nPR:L - The driver performs no capability or namespace-specific check, so an ordinary account granted access to the VME device node can configure and trigger the flaw. Although devtmpfs defaults to root-owned mode 0600, non-root access for an industrial control or service account is a reasonable deployment.\nUI:N - The attacker independently performs the configuration and malicious read or write without requiring any victim action.\nS:U - Exploitation compromises the host kernel within the same security authority. This is a standard local privilege-escalation condition, not a VM, sandbox, or IOMMU boundary escape.\nC:H - The read path copies an attacker-selected, potentially very large range of kernel memory beyond the 128 KiB allocation to userspace. This can disclose adjacent allocations, kernel pointers, credentials, and other sensitive memory.\nI:H - The write path copies attacker-controlled bytes beyond the DMA or large-kmalloc allocation, potentially across many adjacent physical pages. This provides exploitable memory corruption capable of modifying kernel objects or achieving control-flow hijacking.\nA:H - The out-of-bounds write was confirmed to trigger a KASAN kernel memory-safety failure and can corrupt or access invalid adjacent memory. A kernel oops or panic can be triggered without user interaction."
    }
  }
}