{"api_version":"1","generated_at":"2026-08-17T11:26:45+00:00","cve":"CVE-2026-74573","urls":{"html":"https://cve.report/CVE-2026-74573","api":"https://cve.report/api/cve/CVE-2026-74573.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74573","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74573"},"summary":{"title":"iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE","description":"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's vSID to a single physical Stream ID\ntaken from master->streams[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' ATC and IOTLB entries; a device with\nnone makes master->streams a ZERO_SIZE_PTR, read out of bounds.\n\nAdd an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP\nwhen master->num_streams is not one, rather than mapping it silently.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:18:02","updated_at":"2026-08-17 06:19:55"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.3","severity":"CRITICAL","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","baseScore":9.3,"baseSeverity":"CRITICAL","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.3","severity":"CRITICAL","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","data":{"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"}}],"references":[{"url":"https://git.kernel.org/stable/c/3808bab5d95ae79e333e11f6a73d178e084c645d","name":"https://git.kernel.org/stable/c/3808bab5d95ae79e333e11f6a73d178e084c645d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0acbc621341aca4eb94d9c2f43e1ab273ff088f0","name":"https://git.kernel.org/stable/c/0acbc621341aca4eb94d9c2f43e1ab273ff088f0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c3b8ee84a965058b41275069d4696f37a8b14bf6","name":"https://git.kernel.org/stable/c/c3b8ee84a965058b41275069d4696f37a8b14bf6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74573","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74573","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d68beb276ba26cec47350a6d468e967673ee0c56 3808bab5d95ae79e333e11f6a73d178e084c645d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d68beb276ba26cec47350a6d468e967673ee0c56 0acbc621341aca4eb94d9c2f43e1ab273ff088f0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d68beb276ba26cec47350a6d468e967673ee0c56 c3b8ee84a965058b41275069d4696f37a8b14bf6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.13","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.44 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.8 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74573","cve":"CVE-2026-74573","epss":"0.001550000","percentile":"0.051100000","score_date":"2026-08-16","updated_at":"2026-08-17 00:01:04"},"legacy_qids":[]},"source_records":{"cve_program":{"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"}]},{"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"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"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's vSID to a single physical Stream ID\ntaken from master->streams[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' ATC and IOTLB entries; a device with\nnone makes master->streams a ZERO_SIZE_PTR, read out of bounds.\n\nAdd an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP\nwhen master->num_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—an 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->streams[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->streams[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"},"nvd":{"publishedDate":"2026-08-15 13:18:02","lastModifiedDate":"2026-08-17 06:19:55","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","baseScore":9.3,"baseSeverity":"CRITICAL","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.5,"impactScore":6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74573","Ordinal":"1","Title":"iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a v","CVE":"CVE-2026-74573","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74573","Ordinal":"1","NoteData":"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's vSID to a single physical Stream ID\ntaken from master->streams[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' ATC and IOTLB entries; a device with\nnone makes master->streams a ZERO_SIZE_PTR, read out of bounds.\n\nAdd an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP\nwhen master->num_streams is not one, rather than mapping it silently.","Type":"Description","Title":"iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a v"}]}}}