CVE-2026-89442 (GCVE-0-2026-89442)
Vulnerability from cvelistv5
Published
2026-09-11 19:43
Modified
2026-10-19 08:46
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: platform/x86: ISST: Validate socket ID in clos_assoc ioctl isst_if_clos_assoc() validates the user-supplied socket_id with 'socket_id > topology_max_packages()', but isst_common.sst_inst[] is allocated with topology_max_packages() entries, so the valid index range is [0, topology_max_packages()). The '>' comparison lets socket_id == topology_max_packages() pass and index one entry past the array. In addition, isst_common.sst_inst[socket_id] is NULL for an in-range package that has no bound TPMI SST instance, and the pointer is used without a NULL check. Both the out-of-bounds entry and the NULL pointer are then dereferenced by map_partition_power_domain_id() and the following power_domain_info access. Reject socket_id >= topology_max_packages() and a NULL sst_inst, matching the checks already performed by get_instance().
References
Impacted products
Vendor Product Version
Linux Linux Version: 12a7d2cb811dd8a884dea088a2701fcb8d00136e
Version: 12a7d2cb811dd8a884dea088a2701fcb8d00136e
Version: 12a7d2cb811dd8a884dea088a2701fcb8d00136e
Version: 12a7d2cb811dd8a884dea088a2701fcb8d00136e
Version: 12a7d2cb811dd8a884dea088a2701fcb8d00136e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c"
          ],
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          "product": "Linux",
          "programFiles": [
            "drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.4"
            },
            {
              "lessThan": "6.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
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              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
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              "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": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86: ISST: Validate socket ID in clos_assoc ioctl\n\nisst_if_clos_assoc() validates the user-supplied socket_id with\n\u0027socket_id \u003e topology_max_packages()\u0027, but isst_common.sst_inst[] is\nallocated with topology_max_packages() entries, so the valid index range\nis [0, topology_max_packages()).  The \u0027\u003e\u0027 comparison lets\nsocket_id == topology_max_packages() pass and index one entry past the\narray.\n\nIn addition, isst_common.sst_inst[socket_id] is NULL for an in-range\npackage that has no bound TPMI SST instance, and the pointer is used\nwithout a NULL check.  Both the out-of-bounds entry and the NULL pointer\nare then dereferenced by map_partition_power_domain_id() and the\nfollowing power_domain_info access.\n\nReject socket_id \u003e= topology_max_packages() and a NULL sst_inst, matching\nthe checks already performed by get_instance()."
        }
      ],
      "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 bug is reached only through the ISST_IF_CLOS_ASSOC ioctl on /dev/isst_interface; isst_if_clos_assoc() is not invoked from network, Bluetooth, or USB processing.\nAC:L - The attacker sets punit_cpu_map=1 and socket_id equal to topology_max_packages() (one past sst_inst[]) or to an in-range unbound package (NULL sst_inst). Both are deterministic ioctl inputs with no race or victim state.\nPR:L - isst_if_open() has no capability check, and capable(CAP_SYS_ADMIN) runs only on the SET path after sst_inst is already indexed and dereferenced, so an unprivileged local user with the device fd can trigger it via GET.\nUI:N - The attacker issues the ioctl directly against /dev/isst_interface; no victim action such as mounting a filesystem or opening a file is required.\nS:U - The out-of-bounds pointer load and subsequent NULL or wild dereference stay in the kernel ISST driver and do not cross a VM, IOMMU, or sandbox boundary.\nC:H - socket_id == topology_max_packages() reads one pointer past sst_inst[] and treats it as struct tpmi_sst_struct; map_partition_power_domain_id() and readq() follow that object, and GET copy_to_user discloses the result as a kernel-memory read primitive.\nI:H - Treating the adjacent out-of-bounds pointer as sst_inst is type confusion; the confused object supplies sst_base used for writeq() on the SET path and further structure walks, which is an exploitable kernel write primitive.\nA:H - A NULL sst_inst or garbage out-of-bounds pointer is immediately dereferenced in map_partition_power_domain_id() and the following power_domain_info access, causing a kernel oops or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:46:51.770Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c847ea4851ecfa3462cc711ded2c3c3dd8d08ab8"
        },
        {
          "url": "https://git.kernel.org/stable/c/0d90ab5f80e19cddfeb0c9fab47a1f34aa932075"
        },
        {
          "url": "https://git.kernel.org/stable/c/82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca"
        },
        {
          "url": "https://git.kernel.org/stable/c/207b4dc6eb100141b122b2602504a1429a4b6558"
        },
        {
          "url": "https://git.kernel.org/stable/c/a89f07db0cb95c54dac4a8406c79a04e44a73c3c"
        }
      ],
      "title": "platform/x86: ISST: Validate socket ID in clos_assoc ioctl",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89442",
    "datePublished": "2026-09-11T19:43:10.753Z",
    "dateReserved": "2026-09-11T19:38:34.703Z",
    "dateUpdated": "2026-10-19T08:46:51.770Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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