CVE-2026-89795

Estado: RecibidaAlta (8.4)—

In the Linux kernel, the following vulnerability has been resolved:

PCI: Allow per function PCI slots to fix slot reset on s390

On s390 systems, which use a machine level hypervisor, PCI devices are always accessed through a form of PCI pass-through which fundamentally operates on a per PCI function granularity. This is also reflected in the s390 PCI hotplug driver which creates hotplug slots for individual PCI functions. Its reset_slot() function, which is a wrapper for zpci_hot_reset_device(), thus also resets individual functions.

Currently, the pci_create_slot() assigns the same pci_slot object to multifunction devices.

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This approach worked fine on s390 systems that only exposed virtual functions as individual PCI domains to the operating system. Since commit 44510d6fa0c0 ("s390/pci: Handling multifunctions") s390 supports exposing the topology of multifunction PCI devices by grouping them in a shared PCI domain. This creates a problem when resetting a function through the hotplug driver's slot_reset() interface.

When attempting to reset a function through the hotplug driver, the shared slot assignment causes the wrong function to be reset instead of the intended one. It also leaks memory as we do create a pci_slot object for the function, but don't correctly free it in pci_slot_release().

Add a flag for struct pci_slot to allow per function PCI slots for functions managed through a hypervisor, which exposes individual PCI functions while retaining the topology. Since we can use all 8 bits for slot 'number' (for ARI devices), change slot 'number' u16 to account for special values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
Puntuación base: 8.4

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.17%
Percentil entre todas las CVEs puntuadas: 6
Fecha de la puntuación: 4/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation75 %
Impacto principalT1565.001 Stored Data Manipulationimpact60 %
Impacto secundarioT1499.004 Application or System Exploitationimpact55 %

Vulnerabilidad local en kernel que permite escalada de privilegios (PR:L sin UI:N, S:C con I:H/A:H) mediante manipulación de función PCI; riesgo de corrupción de datos y denegación de servicio en s390.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence Program Restrict File and Directory Permissions Remote Data Storage Filter Network Traffic Execution Prevention Encrypt Sensitive Information

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-89795",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.4,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 5.8,
        "exploitabilityScore": 2
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "lessThan": "0d1a7d67f45645106578d65181e4e492dd20ed79",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "lessThan": "2050d900f9adbd6d6f38d30e182bcd9ad3108467",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "lessThan": "ecdcceed4d377b02d4ea036b65f83f962c38ede7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "lessThan": "dcc5bec09e23bbc4f9de055a11fce9937244f2c8",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/pci/pci.c",
            "drivers/pci/slot.c",
            "include/linux/pci.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.8",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/pci/pci.c",
            "drivers/pci/slot.c",
            "include/linux/pci.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-16T11:16:44.307",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0d1a7d67f45645106578d65181e4e492dd20ed79",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2050d900f9adbd6d6f38d30e182bcd9ad3108467",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dcc5bec09e23bbc4f9de055a11fce9937244f2c8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ecdcceed4d377b02d4ea036b65f83f962c38ede7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: Allow per function PCI slots to fix slot reset on s390\n\nOn s390 systems, which use a machine level hypervisor, PCI devices are\nalways accessed through a form of PCI pass-through which fundamentally\noperates on a per PCI function granularity. This is also reflected in the\ns390 PCI hotplug driver which creates hotplug slots for individual PCI\nfunctions. Its reset_slot() function, which is a wrapper for\nzpci_hot_reset_device(), thus also resets individual functions.\n\nCurrently, the pci_create_slot() assigns the same pci_slot object to\nmultifunction devices. This approach worked fine on s390 systems that only\nexposed virtual functions as individual PCI domains to the operating\nsystem.  Since commit 44510d6fa0c0 (\"s390/pci: Handling multifunctions\")\ns390 supports exposing the topology of multifunction PCI devices by\ngrouping them in a shared PCI domain. This creates a problem when resetting\na function through the hotplug driver's slot_reset() interface.\n\nWhen attempting to reset a function through the hotplug driver, the shared\nslot assignment causes the wrong function to be reset instead of the\nintended one. It also leaks memory as we do create a pci_slot object for\nthe function, but don't correctly free it in pci_slot_release().\n\nAdd a flag for struct pci_slot to allow per function PCI slots for\nfunctions managed through a hypervisor, which exposes individual PCI\nfunctions while retaining the topology. Since we can use all 8 bits for\nslot 'number' (for ARI devices), change slot 'number' u16 to account for\nspecial values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES."
    }
  ],
  "lastModified": "2026-10-03T11:17:43.450",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}