CVE-2026-74573 (GCVE-0-2026-74573)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:28 – Updated: 2026-08-17 05:48
VLAI
Title
iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE
Summary
In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE arm_vsmmu_vsid_to_sid() maps a guest's vSID to a single physical Stream ID taken from master->streams[0], assuming a device has exactly one stream. A device with several streams gets only its first one mapped, so a guest vSID invalidation cannot reach the others' ATC and IOTLB entries; a device with none makes master->streams a ZERO_SIZE_PTR, read out of bounds. Add an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP when master->num_streams is not one, rather than mapping it silently.
Severity
9.3 (Critical)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: d68beb276ba26cec47350a6d468e967673ee0c56 , < 3808bab5d95ae79e333e11f6a73d178e084c645d (git)
Affected: d68beb276ba26cec47350a6d468e967673ee0c56 , < 0acbc621341aca4eb94d9c2f43e1ab273ff088f0 (git)
Affected: d68beb276ba26cec47350a6d468e967673ee0c56 , < c3b8ee84a965058b41275069d4696f37a8b14bf6 (git)
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Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3808bab5d95ae79e333e11f6a73d178e084c645d",
              "status": "affected",
              "version": "d68beb276ba26cec47350a6d468e967673ee0c56",
              "versionType": "git"
            },
            {
              "lessThan": "0acbc621341aca4eb94d9c2f43e1ab273ff088f0",
              "status": "affected",
              "version": "d68beb276ba26cec47350a6d468e967673ee0c56",
              "versionType": "git"
            },
            {
              "lessThan": "c3b8ee84a965058b41275069d4696f37a8b14bf6",
              "status": "affected",
              "version": "d68beb276ba26cec47350a6d468e967673ee0c56",
              "versionType": "git"
            }
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          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.13"
            },
            {
              "lessThan": "6.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.44",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.8",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE\n\narm_vsmmu_vsid_to_sid() maps a guest\u0027s vSID to a single physical Stream ID\ntaken from master-\u003estreams[0], assuming a device has exactly one stream. A\ndevice with several streams gets only its first one mapped, so a guest vSID\ninvalidation cannot reach the others\u0027 ATC and IOTLB entries; a device with\nnone makes master-\u003estreams a ZERO_SIZE_PTR, read out of bounds.\n\nAdd an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP\nwhen master-\u003enum_streams is not one, rather than mapping it silently."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires reaching arm_vsmmu_cache_invalidate() via the IOMMU_HWPT_INVALIDATE ioctl on /dev/iommu (or VFIO-compat fd), a local syscall path from a process or VMM forwarding guest nested-IOMMU invalidations to the host kernel.\nAC:L - Once a vDEVICE is registered on an ARM SMMUv3 vIOMMU with a multi-stream or zero-stream master, the attacker reliably issues ATC_INV/CFGI_CD invalidation commands; no race or uncontrollable memory layout is required beyond having such hardware attached.\nPR:N - A malicious guest or tenant VM with passed-through PCI and nested vIOMMU needs no host root or credentials; QEMU normally forwards guest IOMMU invalidations to host iommufd, reaching the vulnerable code without any host authentication or admin privilege.\nUI:N - Exploitation is fully attacker-driven through iommufd ioctls and does not require any victim user action such as opening files, clicking links, or mounting filesystems beyond the attacker-controlled device setup.\nS:C - Incomplete vSID-to-SID mapping leaves stale ATC/IOTLB entries on additional Stream IDs, allowing device DMA to bypass the guest nested IOMMU policy and reach host physical memory outside the guest security domain\u2014an IOMMU/DMA boundary violation.\nC:H - Stale translations on un-invalidated streams let a malicious guest or local user read host memory via DMA using cached mappings; the num_streams==0 path also performs an out-of-bounds read of master-\u003estreams[0].id from ZERO_SIZE_PTR, leaking kernel memory into the SID field.\nI:H - Stale IOTLB/ATC entries enable arbitrary DMA writes to previously mapped host pages, and the leaked/garbage SID from the out-of-bounds streams[0] read can target invalidation at unintended Stream IDs, corrupting IOMMU translation state.\nA:H - The zero-stream case dereferences master-\u003estreams[0] when streams is ZERO_SIZE_PTR, which can kernel-oops the host; even without a crash, stale TLB state enables sustained hostile DMA that can destabilize the system."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:52.745Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3808bab5d95ae79e333e11f6a73d178e084c645d"
        },
        {
          "url": "https://git.kernel.org/stable/c/0acbc621341aca4eb94d9c2f43e1ab273ff088f0"
        },
        {
          "url": "https://git.kernel.org/stable/c/c3b8ee84a965058b41275069d4696f37a8b14bf6"
        }
      ],
      "title": "iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74573",
    "datePublished": "2026-08-15T12:28:11.935Z",
    "dateReserved": "2026-08-15T05:44:03.917Z",
    "dateUpdated": "2026-08-17T05:48:52.745Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-20",
      "epss": "0.00131",
      "percentile": "0.0305"
    },
    "nvd": {
      "cve": {
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                "vendor": "Linux",
                "versions": [
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                    "versionType": "semver"
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                    "versionType": "semver"
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                    "status": "unaffected",
                    "version": "7.1.8",
                    "versionType": "semver"
                  },
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                    "versionType": "original_commit_for_fix"
                  }
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              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE\n\narm_vsmmu_vsid_to_sid() maps a guest\u0027s vSID to a single physical Stream ID\ntaken from master-\u003estreams[0], assuming a device has exactly one stream. A\ndevice with several streams gets only its first one mapped, so a guest vSID\ninvalidation cannot reach the others\u0027 ATC and IOTLB entries; a device with\nnone makes master-\u003estreams a ZERO_SIZE_PTR, read out of bounds.\n\nAdd an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP\nwhen master-\u003enum_streams is not one, rather than mapping it silently."
          }
        ],
        "id": "CVE-2026-74573",
        "lastModified": "2026-08-17T06:19:55.640",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 9.3,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
                "version": "3.1"
              },
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              "impactScore": 6.0,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-15T13:18:02.963",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0acbc621341aca4eb94d9c2f43e1ab273ff088f0"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/3808bab5d95ae79e333e11f6a73d178e084c645d"
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          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-17T12:47:09+00:00",
      "cve": "CVE-2026-74573",
      "id": "CVE-2026-74573",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74573.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-18T16:53:29Z",
      "cve": "CVE-2026-74573",
      "id": "CVE-2026-74573",
      "initial_release_date": "2026-08-15T23:49:53Z",
      "product_status:known_not_affected": "284",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74573",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74573.json",
      "version": "4"
    }
  }
}



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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.


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