GHSA-F42M-8RH7-XP4F

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer

adm1266_pmbus_block_xfer() sets up the read transaction with

.buf = data->read_buf,
.len = ADM1266_PMBUS_BLOCK_MAX + 2,

but read_buf in struct adm1266_data is declared as

u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1];

For a max-length block response (length byte = 255 + up to 1 PEC byte), the i2c controller is told to write 257 bytes into a 256-byte buffer, putting one byte past the end of read_buf. The same response also makes the subsequent PEC compare

if (crc != msgs[1].buf[msgs[1].buf[0] + 1])

read a byte beyond the array.

Bump the read_buf declaration to ADM1266_PMBUS_BLOCK_MAX + 2 so the buffer can hold the length byte, up to 255 payload bytes, and the PEC byte the i2c_msg length already accounts for.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64086"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:49Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer\n\nadm1266_pmbus_block_xfer() sets up the read transaction with\n\n\t.buf = data-\u003eread_buf,\n\t.len = ADM1266_PMBUS_BLOCK_MAX + 2,\n\nbut read_buf in struct adm1266_data is declared as\n\n\tu8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1];\n\nFor a max-length block response (length byte = 255 + up to 1 PEC\nbyte), the i2c controller is told to write 257 bytes into a 256-byte\nbuffer, putting one byte past the end of read_buf.  The same response\nalso makes the subsequent PEC compare\n\n\tif (crc != msgs[1].buf[msgs[1].buf[0] + 1])\n\nread a byte beyond the array.\n\nBump the read_buf declaration to ADM1266_PMBUS_BLOCK_MAX + 2 so the\nbuffer can hold the length byte, up to 255 payload bytes, and the PEC\nbyte the i2c_msg length already accounts for.",
  "id": "GHSA-f42m-8rh7-xp4f",
  "modified": "2026-07-20T15:31:59Z",
  "published": "2026-07-19T18:31:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64086"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2279c342d94eca225bf9f301c8806a05a1c81619"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/397d3f523bfff2f4e3dacf9b1339bd76dc207f78"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/472744f69d25a2d5111ad62f1d62579dce2c13c8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/487566cb1ccdf3756fdd7bf8d875e612ff3169bb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/528a9f88e88502d0c2f2052a279415074cd83715"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a6c802145a8de0830bca803c6d415f7e9e683624"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d94ceb16e55b6d8019ab069e357c76ac42f0ffbc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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