CVE-2026-81012 (GCVE-0-2026-81012)
Vulnerability from cvelistv5
Published
2026-09-11 19:43
Modified
2026-10-19 08:46
Severity ?
8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: platform/x86: hp-bioscfg: fix off-by-one write in hp_get_string_from_buffer() hp_get_string_from_buffer() clamps the converted string length against the destination buffer size with "size > dst_size", so when the converted length is exactly equal to dst_size, conv_dst_size is left at dst_size and the unconditional NUL terminator write dst[conv_dst_size] = 0; lands one byte past the destination buffer. This is the same shape of bug as the previously fixed off-by-one in hp_convert_hexstr_to_str(): the buffer is sized correctly for the content, but the terminator write is never checked against that size. Fix by changing the comparison to ">=" so conv_dst_size is always left with room for the terminator. All fixed-size destinations that reach this function (path[512], current_value[512], current_password/current_value[64], and the per-entry buffers in encodings[][512] and prerequisites[][512]) are affected.
References
Impacted products
Vendor Product Version
Linux Linux Version: a34fc329b1895fc8a6eb12099adc47009421ba6a
Version: a34fc329b1895fc8a6eb12099adc47009421ba6a
Version: a34fc329b1895fc8a6eb12099adc47009421ba6a
Version: a34fc329b1895fc8a6eb12099adc47009421ba6a
Version: a34fc329b1895fc8a6eb12099adc47009421ba6a
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/platform/x86/hp/hp-bioscfg/bioscfg.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "8f5aa1506cdddea6b33584c2445b9ce99eeddb64",
              "status": "affected",
              "version": "a34fc329b1895fc8a6eb12099adc47009421ba6a",
              "versionType": "git"
            },
            {
              "lessThan": "3cc772d0154799961f032e5a992d4a50523e291a",
              "status": "affected",
              "version": "a34fc329b1895fc8a6eb12099adc47009421ba6a",
              "versionType": "git"
            },
            {
              "lessThan": "b15b334fbc3c0c46440f8a892ebf62164fca23d6",
              "status": "affected",
              "version": "a34fc329b1895fc8a6eb12099adc47009421ba6a",
              "versionType": "git"
            },
            {
              "lessThan": "ddf98cf33529714b3ba1a158afb1db5b0f759a1a",
              "status": "affected",
              "version": "a34fc329b1895fc8a6eb12099adc47009421ba6a",
              "versionType": "git"
            },
            {
              "lessThan": "dc03f05e419f3460342fb7564884f244622634b6",
              "status": "affected",
              "version": "a34fc329b1895fc8a6eb12099adc47009421ba6a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/platform/x86/hp/hp-bioscfg/bioscfg.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86: hp-bioscfg: fix off-by-one write in hp_get_string_from_buffer()\n\nhp_get_string_from_buffer() clamps the converted string length against\nthe destination buffer size with \"size \u003e dst_size\", so when the\nconverted length is exactly equal to dst_size, conv_dst_size is left\nat dst_size and the unconditional NUL terminator write\n\n\tdst[conv_dst_size] = 0;\n\nlands one byte past the destination buffer. This is the same shape of\nbug as the previously fixed off-by-one in hp_convert_hexstr_to_str():\nthe buffer is sized correctly for the content, but the terminator\nwrite is never checked against that size.\n\nFix by changing the comparison to \"\u003e=\" so conv_dst_size is always left\nwith room for the terminator.\n\nAll fixed-size destinations that reach this function (path[512],\ncurrent_value[512], current_password/current_value[64], and the\nper-entry buffers in encodings[][512] and prerequisites[][512]) are\naffected."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - hp_get_string_from_buffer() runs during local hp-bioscfg initialization while parsing HP WMI/ACPI BIOS attribute buffers from wmi_query_block(); there is no network, Bluetooth, or USB protocol path into this UTF-16 conversion.\nAC:L - A WMI buffer whose converted string length equals the destination size deterministically writes the NUL terminator one byte past the buffer; firmware controls the length prefix and contents, with no race or attacker-uncontrollable layout required to trigger the overflow.\nPR:N - The overflow executes automatically in hp_init()/hp_init_bios_attributes() while parsing firmware-supplied WMI buffers, with no Linux user account, capability, or sysfs check on that path; a supply-chain or compromised HP BIOS suffices.\nUI:N - Every WMI BIOS attribute instance is parsed automatically at boot or module load; exploitation does not require a victim to mount a filesystem, open a file, or take any other action.\nS:U - The out-of-bounds write corrupts kernel heap or stack in the same host kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - The one-byte overflow past heap objects (including a kcalloc buffer sized from the remaining WMI payload) and kernel-stack name buffers corrupts adjacent objects or pointer LSBs, which is leverageable for kernel memory disclosure.\nI:H - This is an out-of-bounds write past fixed-size fields and a separately allocated heap buffer whose size is chosen from the firmware buffer length, giving a slab-adjacent write primitive usable for control-flow hijacking after heap grooming.\nA:H - Writing one byte past a kmalloc object or kernel stack buffer can corrupt adjacent pointers or slab metadata and cause a kernel oops, KASAN abort, or panic during hp-bioscfg bring-up."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:46:37.440Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8f5aa1506cdddea6b33584c2445b9ce99eeddb64"
        },
        {
          "url": "https://git.kernel.org/stable/c/3cc772d0154799961f032e5a992d4a50523e291a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b15b334fbc3c0c46440f8a892ebf62164fca23d6"
        },
        {
          "url": "https://git.kernel.org/stable/c/ddf98cf33529714b3ba1a158afb1db5b0f759a1a"
        },
        {
          "url": "https://git.kernel.org/stable/c/dc03f05e419f3460342fb7564884f244622634b6"
        }
      ],
      "title": "platform/x86: hp-bioscfg: fix off-by-one write in hp_get_string_from_buffer()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-81012",
    "datePublished": "2026-09-11T19:43:02.082Z",
    "dateReserved": "2026-08-26T14:34:25.813Z",
    "dateUpdated": "2026-10-19T08:46:37.440Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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