{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/platform/x86/panasonic-laptop.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a93df956ee4d903735b6d395362c839cb1dc07e3",
              "status": "affected",
              "version": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4",
              "versionType": "git"
            },
            {
              "lessThan": "329f10d8be193bf36af124e00b9dd6644cd71724",
              "status": "affected",
              "version": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/platform/x86/panasonic-laptop.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "lessThan": "7.2",
              "status": "unaffected",
              "version": "0",
              "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": "7.2.4",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86: panasonic-laptop: Fix sentinel write past pcc-\u003esinf[]\n\nacpi_pcc_retrieve_biosdata() rejects SINF packages only when\npcc-\u003enum_sifr is strictly less than hkey-\u003epackage.count, then\nunconditionally writes a trailing sentinel at\npcc-\u003esinf[hkey-\u003epackage.count]. But pcc-\u003esinf[] is allocated with\nexactly pcc-\u003enum_sifr elements (valid indices 0..num_sifr-1), so that\nwrite needs num_sifr strictly greater than package.count to stay in\nbounds -- num_sifr == package.count passes the existing check but\nstill overflows by one element.\n\nThis is exactly the case probe()\u0027s existing num_sifr++ workaround\n(\"Some DSDT-s have an off-by-one bug where the SINF package count is\none higher than the SQTY reported value\") is written to accommodate:\nwhen a DSDT\u0027s SINF package count equals SQTY+1, the workaround makes\nnum_sifr equal to package.count, which is precisely the boundary that\noverflows here. Found via UBSan (array-index-out-of-bounds) on\nhardware where HKEY.SQTY returns 37 and HKEY.SINF()\u0027s package has 38\nelements: num_sifr becomes 38 after the += 1 workaround, the loop\ncorrectly fills indices 0..37, and the sentinel write then targets\nindex 38, one past the end -- a silent 4-byte heap overflow on kernels\nwithout CONFIG_UBSAN.\n\nTightening the rejection check to num_sifr \u003c= package.count would\navoid the overflow but breaks probe() entirely on exactly this\nhardware, since num_sifr == package.count is the case the off-by-one\nworkaround exists to support. Nothing else in the driver reads this\nsentinel value back, so simply skip the write when there is no room\nfor it instead."
        }
      ],
      "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 by reading world-readable sysfs files under /sys/bus/acpi/devices/MAT00xx:00/ (numbatt, lcdtype, mute, sticky_key, eco_mode, brightness) and /sys/class/backlight/panasonic/, which call acpi_pcc_retrieve_biosdata(); there is no network or remote-peer path into this ACPI laptop driver.\nAC:L - On Panasonic Let\u0027s Note firmware where HKEY.SINF\u0027s package count equals SQTY+1, every sysfs or backlight read deterministically writes the sentinel one past pcc-\u003esinf[]; no race is required. That DSDT off-by-one is a fixed property of the affected hardware being scored, not a per-attempt condition.\nPR:L - The triggering attributes are DEVICE_ATTR_RO (0444) or DEVICE_ATTR_RW (0644), so any unprivileged local user can read them and cause the out-of-bounds write with no capability, group membership, or init-namespace root.\nUI:N - The attacker reads a sysfs attribute from their own process; no victim action such as mounting a filesystem, plugging hardware, or confirming a prompt is required.\nS:U - The 4-byte heap overflow corrupts host kernel slab memory belonging to the same kernel security authority that hosts the driver; it does not cross a VM, IOMMU, or sandbox boundary.\nC:H - The off-by-one writes 0xffffffff one u32 past the kzalloc_flex pcc_acpi object, corrupting adjacent kmalloc slab contents including pointers on size-class-aligned allocations; that heap corruption can be leveraged for kernel information disclosure, so confidentiality is High.\nI:H - This is a repeatable 4-byte out-of-bounds heap write of the sentinel past pcc-\u003esinf[]. Per kernel scoring guidance an OOB write is High because heap grooming can place a security-relevant object at the overwritten offset and turn it into a control-flow or privilege primitive.\nA:H - Writing past the kmalloc object can corrupt neighboring slab objects or metadata and produce a kernel oops or panic, and debug kernels trip KASAN/UBSAN on the counted-by overflow; any such crash is Availability High."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:46:44.750Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a93df956ee4d903735b6d395362c839cb1dc07e3"
        },
        {
          "url": "https://git.kernel.org/stable/c/329f10d8be193bf36af124e00b9dd6644cd71724"
        }
      ],
      "title": "platform/x86: panasonic-laptop: Fix sentinel write past pcc-\u003esinf[]",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89436",
    "datePublished": "2026-09-11T19:43:06.732Z",
    "dateReserved": "2026-09-11T19:38:34.702Z",
    "dateUpdated": "2026-10-19T08:46:44.750Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}