CVE-2026-74617 (GCVE-0-2026-74617)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-25 05:40
VLAI
Title
dibs: initialise dibs->lock in dibs_dev_alloc()
Summary
In the Linux kernel, the following vulnerability has been resolved: dibs: initialise dibs->lock in dibs_dev_alloc() dibs->lock is initialised by dibs_dev_add(), but a dibs device can already take interrupts before that call: ism_probe() runs ism_dev_init(), and hence request_irq(), before it calls dibs_dev_add(). No client can have registered a dmb at that point, so no dmb interrupt can occur, but a GID event interrupt can, and ism_handle_irq() takes dibs->lock unconditionally on entry, before it inspects anything else. Initialise the lock in dibs_dev_alloc() instead, so that it is valid as soon as a driver can publish the device to its interrupt handler.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cc21191b584c6f7836b0f10774f8278b7cbfba10 , < fe79571f40434b257d68cbfb7b3ae93a794d8a11 (git)
Affected: cc21191b584c6f7836b0f10774f8278b7cbfba10 , < 2926031acba100d0c18fcfaa7a2ed29609318848 (git)
Affected: cc21191b584c6f7836b0f10774f8278b7cbfba10 , < c27e360545373b7aee9862a5beef3b9fb3df0c25 (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/dibs/dibs_main.c",
            "include/linux/dibs.h"
          ],
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          "vendor": "Linux",
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          "vendor": "Linux",
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              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndibs: initialise dibs-\u003elock in dibs_dev_alloc()\n\ndibs-\u003elock is initialised by dibs_dev_add(), but a dibs device can\nalready take interrupts before that call: ism_probe() runs\nism_dev_init(), and hence request_irq(), before it calls\ndibs_dev_add(). No client can have registered a dmb at that point, so\nno dmb interrupt can occur, but a GID event interrupt can, and\nism_handle_irq() takes dibs-\u003elock unconditionally on entry, before it\ninspects anything else.\n\nInitialise the lock in dibs_dev_alloc() instead, so that it is valid as\nsoon as a driver can publish the device to its interrupt handler."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On IBM Z SMC-D systems, a remote networked peer on the shared ISM fabric can emit GID/IEQ fabric events that raise ISM MSI interrupts during ism_probe, reaching ism_handle_irq() without any local syscall or ioctl on the victim.\nAC:L - The attacker controls timing by repeatedly sending ISM GID/IEQ fabric events (or coordinating with victim reboot/module reprobe) to hit the probe window between request_irq() and dibs_dev_add(), rather than depending on uncontrollable memory layout.\nPR:N - Exploitation is driven by ISM hardware interrupts from fabric events and does not require local credentials, capabilities, or namespaces on the victim; a remote/co-tenant ISM fabric peer can trigger the IRQ path during device bring-up.\nUI:N - The race occurs automatically during kernel boot or ISM driver probe when fabric GID events arrive; no victim user action such as mounting a filesystem or opening a device node is required.\nS:U - The flaw corrupts kernel driver state via an uninitialized spinlock in IRQ context but does not cross a VM, IOMMU, or sandbox security boundary; impact remains within kernel privilege.\nC:H - Calling spin_lock() on an uninitialized dibs-\u003elock is undefined behavior that can corrupt lock metadata and adjacent dibs_dev fields, creating a memory-safety primitive that can be leveraged for arbitrary kernel memory disclosure.\nI:H - Broken spinlock initialization can permit unsafe concurrent access to dibs_dev state and enable arbitrary kernel memory writes or control-flow hijacking, not merely a clean denial of service.\nA:H - Taking an uninitialized spinlock in ism_handle_irq() can trigger kernel BUG/oops/panic or wedge ISM interrupt handling, causing a high-severity system crash or hang on affected IBM Z hosts."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:40:44.661Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/fe79571f40434b257d68cbfb7b3ae93a794d8a11"
        },
        {
          "url": "https://git.kernel.org/stable/c/2926031acba100d0c18fcfaa7a2ed29609318848"
        },
        {
          "url": "https://git.kernel.org/stable/c/c27e360545373b7aee9862a5beef3b9fb3df0c25"
        }
      ],
      "title": "dibs: initialise dibs-\u003elock in dibs_dev_alloc()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74617",
    "datePublished": "2026-08-22T15:32:02.049Z",
    "dateReserved": "2026-08-15T05:44:03.920Z",
    "dateUpdated": "2026-08-25T05:40:44.661Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-01",
      "epss": "0.00442",
      "percentile": "0.36912"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:51:12+00:00",
      "cve": "CVE-2026-74617",
      "id": "CVE-2026-74617",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: dibs: initialise dibs-\u003elock in dibs_dev_alloc()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74617.json",
      "version": "3"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.