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        "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Cloud Linux Inc. and provide a link to the original.",
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        "full_product_name": {
          "name": "linux-headers-4.19.0-28-amd64-0:4.19.325-1+tuxcare.els1.amd64 as a component of Debian 10",
          "product_id": "Debian-10:linux-headers-4.19.0-28-amd64-0:4.19.325-1+tuxcare.els1.amd64"
        },
        "product_reference": "linux-headers-4.19.0-28-amd64-0:4.19.325-1+tuxcare.els1.amd64",
        "relates_to_product_reference": "Debian-10"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "hyperv-daemons-0:4.19.325-1+tuxcare.els1.amd64 as a component of Debian 10",
          "product_id": "Debian-10:hyperv-daemons-0:4.19.325-1+tuxcare.els1.amd64"
        },
        "product_reference": "hyperv-daemons-0:4.19.325-1+tuxcare.els1.amd64",
        "relates_to_product_reference": "Debian-10"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "linux-image-4.19.0-28-amd64-unsigned-0:4.19.325-1+tuxcare.els1.amd64 as a component of Debian 10",
          "product_id": "Debian-10:linux-image-4.19.0-28-amd64-unsigned-0:4.19.325-1+tuxcare.els1.amd64"
        },
        "product_reference": "linux-image-4.19.0-28-amd64-unsigned-0:4.19.325-1+tuxcare.els1.amd64",
        "relates_to_product_reference": "Debian-10"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-64191",
      "cwe": {
        "id": "CWE-125",
        "name": "Out-of-bounds Read"
      },
      "notes": [
        {
          "category": "description",
          "text": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: stub: Reject I2C block transfers with invalid length\n\nThe I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0]\nas the transfer length. The existing check only clamps it to avoid\noverrunning the chip->words[256] register array, but does not validate\nit against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union\ni2c_smbus_data.block buffer (34 bytes total). The driver is a\ndevelopment/test tool (CONFIG_I2C_STUB=m, not built by default)\nthat must be loaded with a chip_addr= parameter.\n\nA local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl\nwith I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing\nstub_xfer() to read or write past the end of the union\ni2c_smbus_data.block buffer:\n\n BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223)\n Read of size 1 at addr ffff88800abcfd92 by task exploit/81\n Call Trace:\n  <TASK>\n  stub_xfer (drivers/i2c/i2c-stub.c:223)\n  __i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593)\n  i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536)\n  i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391)\n  i2cdev_ioctl (drivers/i2c/i2c-dev.c:478)\n  __x64_sys_ioctl (fs/ioctl.c:583)\n  do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n  </TASK>\n\nThe bug exists because i2c-stub implements .smbus_xfer directly,\nbypassing the I2C_SMBUS_BLOCK_MAX validation in\ni2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same\nfunction correctly validates against I2C_SMBUS_BLOCK_MAX, but the\nI2C_SMBUS_I2C_BLOCK_DATA case does not.\n\nFix by rejecting transfers with data->block[0] == 0 or\ndata->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with\nboth the I2C_SMBUS_BLOCK_DATA case in the same function and the\nI2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated().",
          "title": "Vulnerability description"
        }
      ],
      "product_status": {
        "under_investigation": [
          "Debian-10:hyperv-daemons-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:libbpf-dev-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:libbpf4.19-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:libcpupower-dev-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:libcpupower1-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-compiler-gcc-8-x86-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-config-4.19-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-cpupower-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-doc-4.19-0:4.19.325-1+tuxcare.els1.all",
          "Debian-10:linux-headers-4.19.0-28-all-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-headers-4.19.0-28-all-amd64-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-headers-4.19.0-28-amd64-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-headers-4.19.0-28-common-0:4.19.325-1+tuxcare.els1.all",
          "Debian-10:linux-image-4.19.0-28-amd64-unsigned-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-image-amd64-signed-template-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-kbuild-4.19-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-libc-dev-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-perf-4.19-0:4.19.325-1+tuxcare.els1.amd64",
          "Debian-10:linux-source-4.19-0:4.19.325-1+tuxcare.els1.all",
          "Debian-10:linux-support-4.19.0-28-0:4.19.325-1+tuxcare.els1.all"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2026-64191"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/0526931b16e5a118d367b7bfce7d797e63f7ac69",
          "url": "https://git.kernel.org/stable/c/0526931b16e5a118d367b7bfce7d797e63f7ac69"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/1c4ffe6b4f04365485ed58d64c9bb86b46fc9037",
          "url": "https://git.kernel.org/stable/c/1c4ffe6b4f04365485ed58d64c9bb86b46fc9037"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/21e87f336ac6303fed54a69b1d0d79a23b25c8d0",
          "url": "https://git.kernel.org/stable/c/21e87f336ac6303fed54a69b1d0d79a23b25c8d0"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/3fd225f3e4cd67ec8ddab1afed9da03c7c43537c",
          "url": "https://git.kernel.org/stable/c/3fd225f3e4cd67ec8ddab1afed9da03c7c43537c"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/4bd8635f28c135a08aac6badcd7d9b5cdb34335f",
          "url": "https://git.kernel.org/stable/c/4bd8635f28c135a08aac6badcd7d9b5cdb34335f"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/5f4d2bd028ebb6e4c09a9d64842546022321d4a7",
          "url": "https://git.kernel.org/stable/c/5f4d2bd028ebb6e4c09a9d64842546022321d4a7"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e",
          "url": "https://git.kernel.org/stable/c/6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e"
        },
        {
          "category": "external",
          "summary": "https://git.kernel.org/stable/c/7e9072dbd5f2f17934751873450d2c22080ead80",
          "url": "https://git.kernel.org/stable/c/7e9072dbd5f2f17934751873450d2c22080ead80"
        }
      ],
      "release_date": "2026-07-20T17:18:00Z",
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-08-12T13:43:53.375855Z",
          "details": "Affected",
          "product_ids": [
            "Debian-10:hyperv-daemons-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:libbpf-dev-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:libbpf4.19-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:libcpupower-dev-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:libcpupower1-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-compiler-gcc-8-x86-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-config-4.19-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-cpupower-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-doc-4.19-0:4.19.325-1+tuxcare.els1.all",
            "Debian-10:linux-headers-4.19.0-28-all-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-headers-4.19.0-28-all-amd64-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-headers-4.19.0-28-amd64-0:4.19.325-1+tuxcare.els1.amd64",
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            "Debian-10:linux-image-4.19.0-28-amd64-unsigned-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-image-amd64-signed-template-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-kbuild-4.19-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-libc-dev-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-perf-4.19-0:4.19.325-1+tuxcare.els1.amd64",
            "Debian-10:linux-source-4.19-0:4.19.325-1+tuxcare.els1.all",
            "Debian-10:linux-support-4.19.0-28-0:4.19.325-1+tuxcare.els1.all"
          ]
        }
      ]
    }
  ]
}