{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89448", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.706Z", "datePublished": "2026-09-11T19:43:14.746Z", "dateUpdated": "2026-10-19T08:46:57.768Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:46:57.768Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Force requesting ACS when tboot is enabled\n\nCurrently the conditions of requesting ACS in detect_intel_iommu()\ndon't include tboot, leading to a possible misconfiguration with ACS\ndisabled (e.g. due to user opts) while iommu is later forced on by\ntboot_force_iommu().\n\nFix it by checking tboot in detect_intel_iommu()." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - detect_intel_iommu() runs at boot from pci_iommu_alloc() and, when tboot later forces VT-d on, skips pci_request_acs(); a local PCIe/Thunderbolt DMA device or VFIO-passthrough guest can then spoof requester IDs and issue peer-to-peer DMA. This is not a network-protocol path.\nAC:L - On a tboot launch where intel_iommu=off, iommu=off, or default dmar_disabled skipped pci_request_acs(), ACS SV/RR/CR/UF/TB are never programmed; an attacker-controlled device can then deterministically perform P2P DMA or RID spoofing with no race or layout luck.\nPR:N - A malicious PCIe/Thunderbolt device or a tenant with an assigned passthrough/SR-IOV function issues the DMA itself and needs no host account, capability, or init-namespace root, matching other VT-d isolation-bypass scores for unauthenticated devices.\nUI:N - After the kernel boots with tboot-forced VT-d and ACS still disabled, the attacker’s device performs DMA on its own; no separate victim action such as mounting a filesystem or opening a file is required.\nS:C - Missing ACS lets a device spoof requester IDs and send peer-to-peer TLPs that never reach the IOMMU, crossing the device/host DMA isolation boundary that tboot forces VT-d on to enforce (IOMMU/DMA boundary bypass is Scope Changed).\nC:H - Without ACS source validation, request redirect, and translation blocking, a device can impersonate another requester ID or DMA to peer BARs, reading host or peer-device memory outside its IOMMU domain (arbitrary DMA disclosure).\nI:H - The same ACS gap yields DMA writes into host or peer-device memory, including ATS without translation blocking on external/untrusted ports, providing an arbitrary write primitive that can corrupt kernel memory and hijack control flow.\nA:H - Unchecked DMA writes and IOMMU-bypassing P2P traffic can corrupt kernel structures or provoke DMAR faults, oopses, and panics; any such host crash qualifies as High availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/iommu/intel/dmar.c", "drivers/iommu/intel/iommu.c", "drivers/iommu/intel/iommu.h" ], "versions": [ { "version": "5d990b627537e59a3a2f039ff588a4750e9c1a6a", "lessThan": "579eb867d3da63f3b5e32f235925e1daa7ec70d0", "status": "affected", "versionType": "git" }, { "version": "5d990b627537e59a3a2f039ff588a4750e9c1a6a", "lessThan": "aaeb81241e802c86be69394f72d49fde3f861fbb", "status": "affected", "versionType": "git" }, { "version": "5d990b627537e59a3a2f039ff588a4750e9c1a6a", "lessThan": "45705a6bfdb283f7b3b509010fd617b72f942537", "status": "affected", "versionType": "git" }, { "version": "5d990b627537e59a3a2f039ff588a4750e9c1a6a", "lessThan": "87bc611c6c98a41c00feb7b06b0c297dd141a2ae", "status": "affected", "versionType": "git" }, { "version": "5d990b627537e59a3a2f039ff588a4750e9c1a6a", "lessThan": "607432b2618b61df81134be0ef2562b8300c1216", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/iommu/intel/dmar.c", "drivers/iommu/intel/iommu.c", "drivers/iommu/intel/iommu.h" ], "versions": [ { "version": "2.6.33", "status": "affected" }, { "version": "0", "lessThan": "2.6.33", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/579eb867d3da63f3b5e32f235925e1daa7ec70d0" }, { "url": "https://git.kernel.org/stable/c/aaeb81241e802c86be69394f72d49fde3f861fbb" }, { "url": "https://git.kernel.org/stable/c/45705a6bfdb283f7b3b509010fd617b72f942537" }, { "url": "https://git.kernel.org/stable/c/87bc611c6c98a41c00feb7b06b0c297dd141a2ae" }, { "url": "https://git.kernel.org/stable/c/607432b2618b61df81134be0ef2562b8300c1216" } ], "title": "iommu/vt-d: Force requesting ACS when tboot is enabled", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-89448", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:22:16.872682Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:38.787Z" } } ] } }