CVE-2026-89445 (GCVE-0-2026-89445)
Vulnerability from cvelistv5
Published
2026-09-11 19:43
Modified
2026-10-19 08:46
Severity ?
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix UAF in selftest IOPF reporting IOMMUFD selftest TRIGGER_IOPF borrows an attach handle from group->pasid_array without synchronizing against PASID detach, then a concurrent iommu_report_device_fault() can dereference that borrowed handle's domain pointer after the detach erases the handle and frees the backing struct iommufd_attach_handle. TRIGGER_IOPF then dereferences the freed handle, causing a UAF. Fix by adding a iopf_rwsem in mock_dev to follow the expected design of a real driver. Hold its read side across the whole iommu_report_device_fault() call, and its write side around every path that attaches, detaches, or replaces a device domain. This can block new reports and drains in-flight reports before an old attach handle or the IOPF fault parameter can be removed. Also take the write side while registering a mock device, since it can invoke the mock driver's default-domain attach callback.
References
Impacted products
Vendor Product Version
Linux Linux Version: ddee19971081b42615d62f4fdada21274708ed4d
Version: ddee19971081b42615d62f4fdada21274708ed4d
Version: ddee19971081b42615d62f4fdada21274708ed4d
Version: ddee19971081b42615d62f4fdada21274708ed4d
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/iommufd/selftest.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versionType": "git"
            },
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/iommufd/selftest.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommufd: Fix UAF in selftest IOPF reporting\n\nIOMMUFD selftest TRIGGER_IOPF borrows an attach handle from\ngroup-\u003epasid_array without synchronizing against PASID detach,\nthen a concurrent iommu_report_device_fault() can dereference\nthat borrowed handle\u0027s domain pointer after the detach erases\nthe handle and frees the backing struct iommufd_attach_handle.\nTRIGGER_IOPF then dereferences the freed handle, causing a UAF.\n\nFix by adding a iopf_rwsem in mock_dev to follow the expected design\nof a real driver. Hold its read side across the whole\niommu_report_device_fault() call, and its write side around every\npath that attaches, detaches, or replaces a device domain.\nThis can block new reports and drains in-flight reports before an old\nattach handle or the IOPF fault parameter can be removed.\nAlso take the write side while registering a mock device, since\nit can invoke the mock driver\u0027s default-domain attach callback."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached only via local ioctls on /dev/iommu (or VFIO-compat /dev/vfio/vfio): IOMMU_TEST_CMD TRIGGER_IOPF calls iommu_report_device_fault() while a concurrent PASID/RID detach frees the attach handle. No network or packet-receive path exists.\nAC:L - The attacker controls both sides of the race by issuing concurrent IOMMU_TEST_OP_TRIGGER_IOPF and PASID_DETACH/REPLACE or mock-domain destroy on the same fd; iommu_attach_handle_get() does not keep the handle alive after lookup, so no victim timing or uncontrollable layout is required.\nPR:L - iommufd_fops_open() and IOMMU_TEST_CMD perform no capability checks; /dev/iommu is 0660 and MOCK_DOMAIN creates an IOPF-capable mock device without physical assignment, so an unprivileged local user with iommufd access (selftest/syzkaller kernels or VFIO/iommufd group membership) can trigger it without init-namespace root.\nUI:N - Exploitation requires no victim action; the attacker programmatically opens iommufd, creates a mock domain, attaches a PASID, and races TRIGGER_IOPF against detach through their own file descriptors and ioctls.\nS:C - The freed object is struct iommufd_attach_handle used by iommu_report_device_fault() to dispatch domain-\u003eiopf_handler and complete IOMMU page faults; pre-fix TRIGGER_IOPF also accepted any bound idev, so corrupting those handles can hijack IOMMU fault/DMA isolation across the device-assignment boundary.\nC:H - Use-after-free of iommufd_attach_handle lets an attacker reclaim the slab and control the domain pointer later read as attach_handle-\u003edomain-\u003eiopf_handler, enabling arbitrary kernel reads through the IOPF handler and fault-queue path.\nI:H - The UAF is a function-pointer dereference of domain-\u003eiopf_handler plus later handle use in iommufd_fault_iopf_handler; heap spraying yields an arbitrary write and control-flow hijack in the IOMMU fault-completion path.\nA:H - Dereferencing the freed attach handle in find_fault_handler()/iommu_report_device_fault() causes a kernel oops or panic; the UAF is reliably crashable even when not fully exploited for code execution."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:46:54.686Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fd2e7ac94d6d813548b021473c3dddc30c8c07d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/cab2895729516799384d48560e6fca105fb3f927"
        },
        {
          "url": "https://git.kernel.org/stable/c/e27e90bde68b2ab92e63ed19caad1ef57188bea0"
        },
        {
          "url": "https://git.kernel.org/stable/c/8c07df7cdfcf52f1ff276c588612aabc6c6b8399"
        }
      ],
      "title": "iommufd: Fix UAF in selftest IOPF reporting",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89445",
    "datePublished": "2026-09-11T19:43:12.765Z",
    "dateReserved": "2026-09-11T19:38:34.704Z",
    "dateUpdated": "2026-10-19T08:46:54.686Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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