CVE-2026-89795 (GCVE-0-2026-89795)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:30 – Updated: 2026-09-16 14:38
VLAI
Title
PCI: Allow per function PCI slots to fix slot reset on s390
Summary
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. 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.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 44510d6fa0c00aa90b80075caa6b313b25927475 , < 2050d900f9adbd6d6f38d30e182bcd9ad3108467 (git)
Affected: 44510d6fa0c00aa90b80075caa6b313b25927475 , < ecdcceed4d377b02d4ea036b65f83f962c38ede7 (git)
Affected: 44510d6fa0c00aa90b80075caa6b313b25927475 , < dcc5bec09e23bbc4f9de055a11fce9937244f2c8 (git)
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Linux Linux Affected: 5.8
Unaffected: 0 , < 5.8 (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/pci/pci.c",
            "drivers/pci/slot.c",
            "include/linux/pci.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2050d900f9adbd6d6f38d30e182bcd9ad3108467",
              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "versionType": "git"
            },
            {
              "lessThan": "ecdcceed4d377b02d4ea036b65f83f962c38ede7",
              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/pci/pci.c",
            "drivers/pci/slot.c",
            "include/linux/pci.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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\u0027s 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\u0027t 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 \u0027number\u0027 (for ARI devices), change slot \u0027number\u0027 u16 to account for\nspecial values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The flaw is reached from local PCI reset paths (sysfs device reset, VFIO_DEVICE_RESET, and vfio_pci_core_enable()) that call pci_try_reset_function() -\u003e pci_dev_reset_slot_function() -\u003e s390 reset_slot()/zpci_hot_reset_device(); there is no network or adjacent-radio path.\nAC:L - On s390 multifunction domains pci_create_slot() matches PCI_SLOT(devfn) against a full 8-bit slot number, so siblings/VFs are assigned the wrong pci_slot and a reset deterministically invokes the other function\u0027s hotplug reset_slot() with no race or attacker-uncontrollable layout.\nPR:L - vfio_pci_core_enable() and VFIO_DEVICE_RESET call pci_try_reset_function() with no capable() check on the IOMMU path; IBM Z/LinuxONE SR-IOV VF passthrough routinely grants that VFIO fd to an unprivileged qemu/tenant user rather than init-namespace root.\nUI:N - The attacker opens the assigned VFIO device or issues VFIO_DEVICE_RESET themselves; prior admin binding of the zPCI function to vfio-pci is deployment configuration, not victim interaction.\nS:C - Function reset uses the wrongly shared pci_slot and issues zpci_hot_reset_device() on a sibling/PF outside the caller\u0027s VFIO device set, bypassing VFIO\u0027s slot-wide membership check and crossing zPCI per-function isolation into host or other-tenant devices.\nC:N - This is a wrong-function hardware reset plus a pci_slot lifetime leak; it does not perform an out-of-bounds read, use-after-free, or other disclosure of kernel or other users\u0027 memory.\nI:H - zpci_hot_reset_device() disable/re-enable of the unintended function wipes that function\u0027s hardware state behind its owner\u0027s driver, destroying in-flight I/O and device configuration on a host PF or another tenant\u0027s NIC/storage function.\nA:H - Surprise reset of an in-use PF or sibling denies that device and all VFs behind it, and can oops the bound host driver which continues MMIO against a freshly reset zPCI function, causing host kernel availability loss."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:38:44.206Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2050d900f9adbd6d6f38d30e182bcd9ad3108467"
        },
        {
          "url": "https://git.kernel.org/stable/c/ecdcceed4d377b02d4ea036b65f83f962c38ede7"
        },
        {
          "url": "https://git.kernel.org/stable/c/dcc5bec09e23bbc4f9de055a11fce9937244f2c8"
        }
      ],
      "title": "PCI: Allow per function PCI slots to fix slot reset on s390",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89795",
    "datePublished": "2026-09-16T10:30:26.529Z",
    "dateReserved": "2026-09-11T19:38:34.767Z",
    "dateUpdated": "2026-09-16T14:38:44.206Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89795",
      "date": "2026-09-25",
      "epss": "0.00169",
      "percentile": "0.05502"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-23T03:01:40.000Z",
      "cve": "CVE-2026-89795",
      "id": "msrc_CVE-2026-89795",
      "initial_release_date": "2026-09-17T01:02:57.000Z",
      "product_status:known_affected": "2",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "PCI: Allow per function PCI slots to fix slot reset on s390",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89795.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/pci/pci.c",
                  "drivers/pci/slot.c",
                  "include/linux/pci.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "2050d900f9adbd6d6f38d30e182bcd9ad3108467",
                    "status": "affected",
                    "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "ecdcceed4d377b02d4ea036b65f83f962c38ede7",
                    "status": "affected",
                    "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "dcc5bec09e23bbc4f9de055a11fce9937244f2c8",
                    "status": "affected",
                    "version": "44510d6fa0c00aa90b80075caa6b313b25927475",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "drivers/pci/pci.c",
                  "drivers/pci/slot.c",
                  "include/linux/pci.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.8"
                  },
                  {
                    "lessThan": "5.8",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.52",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.2.*",
                    "status": "unaffected",
                    "version": "7.2.5",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.3-rc1",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "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\u0027s 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\u0027t 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 \u0027number\u0027 (for ARI devices), change slot \u0027number\u0027 u16 to account for\nspecial values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES."
          }
        ],
        "id": "CVE-2026-89795",
        "lastModified": "2026-09-16T15:18:09.640",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 8.4,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.0,
              "impactScore": 5.8,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-16T11:16:44.307",
        "references": [
          {
            "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"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-17T16:39:03Z",
      "cve": "CVE-2026-89795",
      "id": "CVE-2026-89795",
      "initial_release_date": "2026-09-17T16:39:03Z",
      "product_status:known_affected": "230",
      "product_status:known_not_affected": "117",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89795",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89795.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.

Sightings

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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.



Related by attack behaviour

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.