{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-64152",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T07:54:57.037Z",
        "datePublished": "2026-07-19T15:40:41.354Z",
        "dateUpdated": "2026-08-05T12:39:46.961Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:39:46.961Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu: Handle unmap error when iommu_debug is enabled\n\nSashiko noticed a latent bug where the map error flow called iommu_unmap()\nwhich calls iommu_debug_unmap_begin()/iommu_debug_unmap_end() however\nsince this is an error path the map flow never actually established the\noriginal iommu_debug_map() it will malfunction.\n\nLift the unmap error handling into iommu_map_nosync() and reorder it so\nthe trace_map()/iommu_debug_map() records the partial mapping and then\nimmediately unmaps it. This avoid creating the unbalanced tracking and\nprovides saner tracing instead of a unmap unmatched to any map."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
                        "baseScore": 7.8,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:L - The vulnerable code is reached only through local kernel IOMMU APIs invoked from userspace ioctl paths such as IOMMUFD IOAS mapping (/dev/iommu) and VFIO DMA mapping (/dev/vfio/vfio), not from any network packet handler.\nAC:H - Exploitation requires CONFIG_IOMMU_DEBUG_PAGEALLOC plus the iommu.debug_pagealloc=1 boot parameter (both admin-controlled debug options absent from production kernels) and a partial IOMMU map failure, conditions the attacker cannot establish unilaterally.\nPR:L - Triggering iommu_map() requires only local userspace access to IOMMUFD or VFIO interfaces (e.g., /dev/vfio/vfio at mode 0666), which an unprivileged local user or cloud VM tenant with assigned passthrough devices can obtain without host root.\nUI:N - No victim interaction is required; the attacker triggers the bug directly through IOMMU map ioctl operations that fail partway through.\nS:C - The bug corrupts IOMMU page-tracking metadata used to enforce the DMA/IOMMU security boundary, and a VM tenant with VFIO passthrough can trigger it in the host kernel, crossing the guest-to-host security authority.\nC:H - Unbalanced debug refcount decrements corrupt page_ext IOMMU tracking state, which can suppress detection of pages still mapped for DMA and thereby permit device reads of host physical memory that should be isolated.\nI:H - Corrupted IOMMU debug tracking is memory corruption in kernel metadata that can mask stale DMA mappings, enabling a device to write host memory across the IOMMU boundary; WARN_ON underflow paths also demonstrate uncontrolled kernel state corruption.\nA:H - The bug triggers WARN_ON on atomic refcount underflow during unmap_begin/dec_page, which can cause kernel oops or panic (especially with panic_on_warn), constituting 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/iommu.c"
                    ],
                    "versions": [
                        {
                            "version": "ccc21213f013834b484cdcc738e282f963fcfc97",
                            "lessThan": "0cd028806efc148a75d4acf711d21db335a89661",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ccc21213f013834b484cdcc738e282f963fcfc97",
                            "lessThan": "0735c54804c709d1b292f3b6947cfb560b2ce552",
                            "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/iommu.c"
                    ],
                    "versions": [
                        {
                            "version": "7.0",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "7.0",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0.11",
                            "lessThanOrEqual": "7.0.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1",
                            "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": "7.0",
                                    "versionEndExcluding": "7.0.11"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "7.0",
                                    "versionEndExcluding": "7.1"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/0cd028806efc148a75d4acf711d21db335a89661"
                },
                {
                    "url": "https://git.kernel.org/stable/c/0735c54804c709d1b292f3b6947cfb560b2ce552"
                }
            ],
            "title": "iommu: Handle unmap error when iommu_debug is enabled",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}