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CVE-2026-89442 (GCVE-0-2026-89442)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-09-14 11:59
VLAI
Title
platform/x86: ISST: Validate socket ID in clos_assoc ioctl
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().
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 12a7d2cb811dd8a884dea088a2701fcb8d00136e , < c847ea4851ecfa3462cc711ded2c3c3dd8d08ab8 (git)
Affected: 12a7d2cb811dd8a884dea088a2701fcb8d00136e , < 0d90ab5f80e19cddfeb0c9fab47a1f34aa932075 (git)
Affected: 12a7d2cb811dd8a884dea088a2701fcb8d00136e , < 82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca (git)
Affected: 12a7d2cb811dd8a884dea088a2701fcb8d00136e , < 207b4dc6eb100141b122b2602504a1429a4b6558 (git)
Affected: 12a7d2cb811dd8a884dea088a2701fcb8d00136e , < a89f07db0cb95c54dac4a8406c79a04e44a73c3c (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.4
Unaffected: 0 , < 6.4 (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
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          "product": "Linux",
          "programFiles": [
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              "version": "6.18.50",
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              "version": "7.2.4",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
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          "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()."
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              "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."
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    "cveId": "CVE-2026-89442",
    "datePublished": "2026-09-11T19:43:10.753Z",
    "dateReserved": "2026-09-11T19:38:34.703Z",
    "dateUpdated": "2026-09-14T11:59:52.425Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
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      "current_release_date": "2026-09-14T21:49:29+00:00",
      "cve": "CVE-2026-89442",
      "id": "CVE-2026-89442",
      "initial_release_date": "2026-09-11T00:00:00+00:00",
      "product_status:known_affected": "185",
      "product_status:known_not_affected": "91",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: platform/x86: ISST: Validate socket ID in clos_assoc ioctl",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89442.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T00:59:20Z",
      "cve": "CVE-2026-89442",
      "id": "CVE-2026-89442",
      "initial_release_date": "2026-09-15T00:59:20Z",
      "product_status:known_affected": "30",
      "product_status:known_not_affected": "323",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89442",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89442.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.