{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4"
            },
            {
              "fixed": "a93df956ee4d903735b6d395362c839cb1dc07e3"
            },
            {
              "fixed": "329f10d8be193bf36af124e00b9dd6644cd71724"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.2.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89436.json"
  },
  "details": "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()'s 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's 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()'s 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.",
  "id": "CVE-2026-89436",
  "modified": "2026-09-15T03:30:22.677339402Z",
  "published": "2026-09-11T19:43:06.732Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/329f10d8be193bf36af124e00b9dd6644cd71724"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a93df956ee4d903735b6d395362c839cb1dc07e3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89436.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89436"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "platform/x86: panasonic-laptop: Fix sentinel write past pcc-\u003esinf[]"
}