CVE-2026-89587 (GCVE-0-2026-89587)
Vulnerability from cvelistv5
Published
2026-09-11 19:44
Modified
2026-10-19 08:49
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: ACPI: pfr_update: fix stack buffer overflow in query_capability() query_capability() copies four ACPI buffer objects returned by the firmware _DSM into fixed-size u8[16] fields in struct pfru_update_cap_info using memcpy with the firmware-supplied length: memcpy(&cap_hdr->code_type, elements[CAP_CODE_TYPE_IDX].buffer.pointer, elements[CAP_CODE_TYPE_IDX].buffer.length); The same pattern repeats for drv_type, platform_id, and oem_id. If the firmware returns buffer.length > 16 for any of these fields, memcpy writes past the destination array. struct pfru_update_cap_info is stack-allocated in pfru_ioctl(). Confirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports are generated when a DSM returns 64-byte buffers, with writes reaching 44 bytes past the end of cap_hdr's [64, 156) frame window into adjacent stack redzones. Introduce a helper pointer to out_obj->package.elements and use it to validate each buffer length against its destination field size before copying, returning -EINVAL if the firmware supplies an oversized buffer.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0db89fa243e5edc5de38c88b369e4c3755c5fb74
Version: 0db89fa243e5edc5de38c88b369e4c3755c5fb74
Version: 0db89fa243e5edc5de38c88b369e4c3755c5fb74
Version: 0db89fa243e5edc5de38c88b369e4c3755c5fb74
Version: 0db89fa243e5edc5de38c88b369e4c3755c5fb74
Version: 0db89fa243e5edc5de38c88b369e4c3755c5fb74
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/acpi/pfr_update.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/acpi/pfr_update.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "lessThan": "5.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "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": "6.1.188",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "5.17",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nACPI: pfr_update: fix stack buffer overflow in query_capability()\n\nquery_capability() copies four ACPI buffer objects returned by the\nfirmware _DSM into fixed-size u8[16] fields in struct\npfru_update_cap_info using memcpy with the firmware-supplied length:\n\n  memcpy(\u0026cap_hdr-\u003ecode_type,\n         elements[CAP_CODE_TYPE_IDX].buffer.pointer,\n         elements[CAP_CODE_TYPE_IDX].buffer.length);\n\nThe same pattern repeats for drv_type, platform_id, and oem_id.\nIf the firmware returns buffer.length \u003e 16 for any of these fields,\nmemcpy writes past the destination array.\n\nstruct pfru_update_cap_info is stack-allocated in pfru_ioctl().\n\nConfirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports\nare generated when a DSM returns 64-byte buffers, with writes reaching\n44 bytes past the end of cap_hdr\u0027s [64, 156) frame window into\nadjacent stack redzones.\n\nIntroduce a helper pointer to out_obj-\u003epackage.elements and use it\nto validate each buffer length against its destination field size\nbefore copying, returning -EINVAL if the firmware supplies an\noversized buffer."
        }
      ],
      "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 overflow is reached only via local ioctl(PFRU_IOC_QUERY_CAP) or write() on /dev/acpi_pfr_updateN (pfru_ioctl/pfru_write \u2192 query_capability). No network, Bluetooth, USB, or packet path evaluates this ACPI _DSM copy.\nAC:L - A single ioctl or write deterministically copies firmware-supplied _DSM buffer lengths into 16-byte stack fields; KASAN reproduced 64-byte DSM buffers writing 44 bytes past cap_hdr. No race or attacker-uncontrollable memory layout is required.\nPR:L - The ioctl/write path has no capable() or namespace check; access is only DAC on the misc device. Although pfrut checks uid 0 and devtmpfs defaults to 0600, Intel PFRU servers reasonably grant /dev/acpi_pfr_updateN to a firmware-management account or container, so privileges are Low.\nUI:N - The attacker opens the device and issues PFRU_IOC_QUERY_CAP or write() themselves; no separate victim action such as mounting a filesystem or opening a hostile file is required.\nS:U - The overflow corrupts the calling task\u0027s kernel stack inside the host kernel. This is local privilege escalation within one security authority, not a VM escape, IOMMU bypass, or sandbox breakout.\nC:H - Firmware-controlled memcpy overflows four u8[16] stack fields and adjacent frame state (KASAN: 44 bytes past cap_hdr), which per kernel guidance is memory corruption leverageable for arbitrary kernel memory disclosure.\nI:H - This is a kernel stack buffer overflow of firmware-controlled length and contents into stack-allocated struct pfru_update_cap_info, overwriting saved registers and the return address and enabling control-flow hijacking.\nA:H - The same out-of-bounds stack writes were confirmed by KASAN and can oops, trip the stack protector, or panic the kernel; the ioctl can be repeated to deny availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:49:19.962Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d3af83e327565a9444cebc0db714cb837e493046"
        },
        {
          "url": "https://git.kernel.org/stable/c/c5a31b4e7e37c92550be9a2edf51ca853a4d251a"
        },
        {
          "url": "https://git.kernel.org/stable/c/a2151624b55029dad0ca7efd17fb83a0461c8843"
        },
        {
          "url": "https://git.kernel.org/stable/c/6d4ed2fd022bc862b156e53aae163b61259e1caa"
        },
        {
          "url": "https://git.kernel.org/stable/c/15d2b7f38f95d28652170344f39ee492c55e567c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ced45be0073a8a31b30b4a7f68cd3a15734515de"
        }
      ],
      "title": "ACPI: pfr_update: fix stack buffer overflow in query_capability()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89587",
    "datePublished": "2026-09-11T19:44:52.066Z",
    "dateReserved": "2026-09-11T19:38:34.729Z",
    "dateUpdated": "2026-10-19T08:49:19.962Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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