CVE-2026-46036 (GCVE-0-2026-46036)
Vulnerability from cvelistv5
Published
2026-05-27 12:56
Modified
2026-08-05 12:29
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: vfio/cdx: Serialize VFIO_DEVICE_SET_IRQS with a per-device mutex vfio_cdx_set_msi_trigger() reads vdev->config_msi and operates on the vdev->cdx_irqs array based on its value, but provides no serialization against concurrent VFIO_DEVICE_SET_IRQS ioctls. Two callers can race such that one observes config_msi as set while another clears it and frees cdx_irqs via vfio_cdx_msi_disable(), resulting in a use-after-free of the cdx_irqs array. Add a cdx_irqs_lock mutex to struct vfio_cdx_device and acquire it in vfio_cdx_set_msi_trigger(), which is the single chokepoint through which all updates to config_msi, cdx_irqs, and msi_count flow, covering both the ioctl path and the close-device cleanup path. This keeps the test of config_msi atomic with the subsequent enable, disable, or trigger operations. Drop the pre-call !cdx_irqs test from vfio_cdx_irqs_cleanup() as part of this change: the optimization it provided is redundant with the !config_msi early-return inside vfio_cdx_msi_disable(), and leaving the test in place would be an unsynchronized read of state the new lock is meant to protect.
References
Impacted products
Vendor Product Version
Linux Linux Version: 848e447e000c41894ff931dc7c004fd42c8840f8
Version: 848e447e000c41894ff931dc7c004fd42c8840f8
Version: 848e447e000c41894ff931dc7c004fd42c8840f8
Version: 848e447e000c41894ff931dc7c004fd42c8840f8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vfio/cdx/intr.c",
            "drivers/vfio/cdx/main.c",
            "drivers/vfio/cdx/private.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ddf96e23c366c566283fce8377928851fa7f5e81",
              "status": "affected",
              "version": "848e447e000c41894ff931dc7c004fd42c8840f8",
              "versionType": "git"
            },
            {
              "lessThan": "7b436ade16cc81095d79b79f8efa3af0a4f5c5a2",
              "status": "affected",
              "version": "848e447e000c41894ff931dc7c004fd42c8840f8",
              "versionType": "git"
            },
            {
              "lessThan": "7530f34ec0ca1438d45a75dcb43183a1cc92eced",
              "status": "affected",
              "version": "848e447e000c41894ff931dc7c004fd42c8840f8",
              "versionType": "git"
            },
            {
              "lessThan": "670e8864b1a218d72f08db40d0103adf38fa1d9b",
              "status": "affected",
              "version": "848e447e000c41894ff931dc7c004fd42c8840f8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vfio/cdx/intr.c",
            "drivers/vfio/cdx/main.c",
            "drivers/vfio/cdx/private.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.86",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.27",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.86",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.27",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.4",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/cdx: Serialize VFIO_DEVICE_SET_IRQS with a per-device mutex\n\nvfio_cdx_set_msi_trigger() reads vdev-\u003econfig_msi and operates on the\nvdev-\u003ecdx_irqs array based on its value, but provides no serialization\nagainst concurrent VFIO_DEVICE_SET_IRQS ioctls.  Two callers can race\nsuch that one observes config_msi as set while another clears it and\nfrees cdx_irqs via vfio_cdx_msi_disable(), resulting in a use-after-free\nof the cdx_irqs array.\n\nAdd a cdx_irqs_lock mutex to struct vfio_cdx_device and acquire it in\nvfio_cdx_set_msi_trigger(), which is the single chokepoint through\nwhich all updates to config_msi, cdx_irqs, and msi_count flow, covering\nboth the ioctl path and the close-device cleanup path.  This keeps the\ntest of config_msi atomic with the subsequent enable, disable, or\ntrigger operations.\n\nDrop the pre-call !cdx_irqs test from vfio_cdx_irqs_cleanup() as part\nof this change: the optimization it provided is redundant with the\n!config_msi early-return inside vfio_cdx_msi_disable(), and leaving the\ntest in place would be an unsynchronized read of state the new lock is\nmeant to protect."
        }
      ],
      "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 via ioctl(VFIO_DEVICE_SET_IRQS) on a local /dev/vfio device file; there is no network or adjacent-network exposure.\nAC:L - This is an attacker-controlled race \u2014 the attacker issues concurrent enable/trigger and disable SET_IRQS ioctls from two threads on the same fd, controlling both sides, and the unserialized core dispatch lets them run in parallel and be hammered until won.\nPR:L - VFIO\u0027s threat model hands the device fd to unprivileged userspace (VM/passthrough processes), so an attacker only needs access to an already-bound vfio-cdx device fd, not init-namespace root; when uncertain, the higher-severity L is chosen.\nUI:N - Triggering the race requires only the attacker\u0027s own concurrent ioctls; no victim action is needed.\nS:U - The use-after-free corrupts the kernel\u0027s own cdx_irqs management array within the kernel security authority and does not cross an IOMMU/VM boundary.\nC:H - Use-after-free of a heap array whose freed contents are read back (including pointers) allows the attacker to reallocate the slab with controlled data and disclose kernel memory.\nI:H - The freed array\u0027s entries (a dereferenced/callable eventfd_ctx pointer and pointers passed to kfree/free_irq) enable heap-spray-based arbitrary write and control-flow hijacking.\nA:H - The use-after-free reliably causes kernel oops/panic when the freed cdx_irqs array is accessed."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:29:15.525Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ddf96e23c366c566283fce8377928851fa7f5e81"
        },
        {
          "url": "https://git.kernel.org/stable/c/7b436ade16cc81095d79b79f8efa3af0a4f5c5a2"
        },
        {
          "url": "https://git.kernel.org/stable/c/7530f34ec0ca1438d45a75dcb43183a1cc92eced"
        },
        {
          "url": "https://git.kernel.org/stable/c/670e8864b1a218d72f08db40d0103adf38fa1d9b"
        }
      ],
      "title": "vfio/cdx: Serialize VFIO_DEVICE_SET_IRQS with a per-device mutex",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46036",
    "datePublished": "2026-05-27T12:56:46.381Z",
    "dateReserved": "2026-05-13T15:03:33.093Z",
    "dateUpdated": "2026-08-05T12:29:15.525Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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