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

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.258, 5.15.209, 6.1.175, 6.12.92, 6.18.34, 6.6.142, 7.0.11
CVEs
CVE-2026-64086
Confirmed fixed CVEs
Not specified
Updated in this feed
7 Nov 2026, 04:43 UTC · Revision 1

Source evidence

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

core-osv · Original source

Published 19 Jul 2026, 15:39 UTC

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.

osv:CVE-2026-64086

Kernel

Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11

Complete source record
{
  "id": "780958b1be585035bfb99c01047d782bfd65011fde0e778aee8f1b3ccf95624f",
  "url": "https://osv.dev/vulnerability/CVE-2026-64086",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer",
    "summary": "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.",
    "evidence": "osv:CVE-2026-64086",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.258",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.209",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.175",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.142",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.92",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.34",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-64086",
      "aliases": [
        "CVE-2026-64086"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
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                },
                {
                  "fixed": "472744f69d25a2d5111ad62f1d62579dce2c13c8"
                },
                {
                  "fixed": "528a9f88e88502d0c2f2052a279415074cd83715"
                },
                {
                  "fixed": "d94ceb16e55b6d8019ab069e357c76ac42f0ffbc"
                },
                {
                  "fixed": "bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694"
                },
                {
                  "fixed": "2279c342d94eca225bf9f301c8806a05a1c81619"
                },
                {
                  "fixed": "a6c802145a8de0830bca803c6d415f7e9e683624"
                },
                {
                  "fixed": "487566cb1ccdf3756fdd7bf8d875e612ff3169bb"
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              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64086.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.10.0"
                },
                {
                  "fixed": "5.10.258"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.209"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
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            },
            {
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                  "introduced": "6.2.0"
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            {
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                  "introduced": "6.7.0"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.34"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.19.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64086.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.885439188Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2279c342d94eca225bf9f301c8806a05a1c81619",
        "https://git.kernel.org/stable/c/397d3f523bfff2f4e3dacf9b1339bd76dc207f78",
        "https://git.kernel.org/stable/c/472744f69d25a2d5111ad62f1d62579dce2c13c8",
        "https://git.kernel.org/stable/c/487566cb1ccdf3756fdd7bf8d875e612ff3169bb",
        "https://git.kernel.org/stable/c/528a9f88e88502d0c2f2052a279415074cd83715",
        "https://git.kernel.org/stable/c/a6c802145a8de0830bca803c6d415f7e9e683624",
        "https://git.kernel.org/stable/c/bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694",
        "https://git.kernel.org/stable/c/d94ceb16e55b6d8019ab069e357c76ac42f0ffbc",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64086.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64086",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64086.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64086",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518222,
  "published_at": "2026-07-19T15:39:56.749+00:00"
}