{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-81007",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-81007"
  ],
  "published": "2026-09-11T19:47:07Z",
  "summary": "ipmi: ipmb: validate write message length",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: ipmb: validate write message length\n\nipmb_write() read message fields before validating the length byte.\n\nA zero or short write can read uninitialized stack bytes.\n\nA length smaller than the SMBus header underflows the block write length.\n\nRequire a non-empty buffer and the minimum IPMB request length.\n\nAlso require the length byte plus payload before parsing the message.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-81007"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8990c7f6bfc1e7689b7012a7d4d0efb9f07a9c89"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/94f8d20153e348c79bc14dc25f873470518892da"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e527cd4e80066e1ed070fdc7c705bde340cdcc62"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7d66d54b974cff0a959e188af844d2d110422767"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/60939bcda6f3f104ef456fdbf3cc5733c0720fb1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5719431ca2b5fa26560bb38f6202f8b97fa3bbb0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a84c6e3d188f2c6e674910929eb790634299d6d5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/53637506884dbd5c91a89b1a3547d99d80f8ed2c"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-14T12:06:03Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.1,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - ipmb_write() is the miscdevice write handler for /dev/ipmb-N and is reached only via a local write(2) on that character device. The I2C slave callback queues inbound IPMB requests for read() and does not enter this path.\nAC:L - A single write of count 0, or a 1-byte write with length field 0, bypasses the old count<msg[0] check and underflows the I2C/SMBus length. The attacker fully controls the buffer; no race or uninfluenced memory layout is required.\nPR:L - Neither ipmb_write() nor misc_open() performs a capability check; access is only DAC on /dev/ipmb-N. BMC and satellite-MC deployments (OpenBMC ipmbbridge, OpenIPMI) commonly grant this node to a non-root management or service account rather than requiring init-namespace root.\nUI:N - The attacker triggers the bug entirely with their own write(2) to an already-present /dev/ipmb-N node. No other user must open a file, mount a filesystem, or otherwise interact.\nS:U - The out-of-bounds stack read and resulting kernel oops remain inside the same host kernel security authority. IPMB/I2C is an in-chassis management bus, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - On i2c-protocol devices (usual OpenBMC/Aspeed DT), a zero length byte promotes to i2c_msg.len 65535, so i2c_transfer/DMA helpers read tens of kilobytes past the 240-byte stack buffer, disclosing kernel stack contents onto the IPMB bus.\nI:N - The defect is an out-of-bounds read of a stack buffer used as an I2C write payload. It does not write kernel memory, corrupt heap objects, or yield a control-flow or arbitrary-write primitive.\nA:H - The 65535-byte stack over-read walks off the kernel stack. Aspeed I2C (typical OpenBMC IPMB adapter) has no max_write_len quirk, so the transfer or memcpy hits the VMAP_STACK guard page and oopses the kernel."
    }
  }
}