CVE-2026-64086 (GCVE-0-2026-64086)
Vulnerability from cvelistv5
Published
2026-07-19 15:39
Modified
2026-08-05 12:39
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
Version: 407dc802a9c0809ca6a48de4b4c63305eb84ef56
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/hwmon/pmbus/adm1266.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "397d3f523bfff2f4e3dacf9b1339bd76dc207f78",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
              "lessThan": "472744f69d25a2d5111ad62f1d62579dce2c13c8",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
              "lessThan": "528a9f88e88502d0c2f2052a279415074cd83715",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
              "lessThan": "d94ceb16e55b6d8019ab069e357c76ac42f0ffbc",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
              "lessThan": "bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
              "lessThan": "2279c342d94eca225bf9f301c8806a05a1c81619",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            },
            {
              "lessThan": "487566cb1ccdf3756fdd7bf8d875e612ff3169bb",
              "status": "affected",
              "version": "407dc802a9c0809ca6a48de4b4c63305eb84ef56",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/hwmon/pmbus/adm1266.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.10"
            },
            {
              "lessThan": "5.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.258",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.209",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.142",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.92",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable code is only reached through local kernel interfaces (debugfs GPIO dump at /sys/kernel/debug/gpio and root-only nvmem blackbox reads), not through any network protocol handler. The ADM1266 sits on an on-board I2C bus on server BMC hardware.\nAC:L - An attacker who controls the I2C bus response (malicious device, compromised ADM1266 firmware, or bus interposition on the BMC) can reliably force a 255-byte block reply whenever a victim triggers the block-transfer path, causing the one-byte overflow on demand.\nPR:L - The gpio debugfs entry is world-readable (0444) if debugfs is mounted and traversable, which occurs on some embedded BMC images without strict permissions; between requiring full init-namespace root and that lower bar, the less privileged path is plausible on misconfigured systems.\nUI:N - Exploitation does not require victim interaction beyond the attacker (or a compromised daemon) programmatically reading debugfs or nvmem; no mount, click, or plug-in action by an end user is needed.\nS:U - Impact is confined to kernel memory corruption within the BMC/host kernel security boundary; this is not a VM escape, IOMMU bypass, or cross-authority sandbox breakout.\nC:H - The PEC validation performs an out-of-bounds read past read_buf, and the one-byte heap overflow can corrupt adjacent kernel objects in ways that enable further memory disclosure primitives.\nI:H - A one-byte, attacker-controlled out-of-bounds write past the end of read_buf into adjacent heap memory can corrupt slab metadata or neighboring objects and be developed into arbitrary write or code-execution primitives.\nA:H - Corrupting adjacent heap objects via the out-of-bounds write can cause kernel oops, panic, or hang on the BMC, denying management-plane availability for the managed server."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:03.986Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/397d3f523bfff2f4e3dacf9b1339bd76dc207f78"
        },
        {
          "url": "https://git.kernel.org/stable/c/472744f69d25a2d5111ad62f1d62579dce2c13c8"
        },
        {
          "url": "https://git.kernel.org/stable/c/528a9f88e88502d0c2f2052a279415074cd83715"
        },
        {
          "url": "https://git.kernel.org/stable/c/d94ceb16e55b6d8019ab069e357c76ac42f0ffbc"
        },
        {
          "url": "https://git.kernel.org/stable/c/bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694"
        },
        {
          "url": "https://git.kernel.org/stable/c/2279c342d94eca225bf9f301c8806a05a1c81619"
        },
        {
          "url": "https://git.kernel.org/stable/c/a6c802145a8de0830bca803c6d415f7e9e683624"
        },
        {
          "url": "https://git.kernel.org/stable/c/487566cb1ccdf3756fdd7bf8d875e612ff3169bb"
        }
      ],
      "title": "hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64086",
    "datePublished": "2026-07-19T15:39:56.749Z",
    "dateReserved": "2026-07-19T07:54:57.032Z",
    "dateUpdated": "2026-08-05T12:39:03.986Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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