{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40058","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.158Z","datePublished":"2025-10-28T11:48:31.567Z","dateUpdated":"2026-08-05T12:07:25.986Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:07:25.986Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Disallow dirty tracking if incoherent page walk\n\nDirty page tracking relies on the IOMMU atomically updating the dirty bit\nin the paging-structure entry. For this operation to succeed, the paging-\nstructure memory must be coherent between the IOMMU and the CPU. In\nanother word, if the iommu page walk is incoherent, dirty page tracking\ndoesn't work.\n\nThe Intel VT-d specification, Section 3.10 \"Snoop Behavior\" states:\n\n\"Remapping hardware encountering the need to atomically update A/EA/D bits\n in a paging-structure entry that is not snooped will result in a non-\n recoverable fault.\"\n\nTo prevent an IOMMU from being incorrectly configured for dirty page\ntracking when it is operating in an incoherent mode, mark SSADS as\nsupported only when both ecap_slads and ecap_smpwc are supported."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable configuration is reached only through local ioctls on /dev/iommu (IOMMU_HWPT_ALLOC with IOMMU_HWPT_ALLOC_DIRTY_TRACKING, then IOMMU_HWPT_SET_DIRTY_TRACKING) against a bound VFIO device fd. There is no network-facing path into the VT-d dirty-tracking code.\nAC:L - On an affected IOMMU the attacker deterministically allocates the dirty-tracking hwpt and enables SSADE with two ioctls — no race to win and no memory layout to groom. Where the IOMMU is emulated for a guest, the ecap_slads=1/ecap_smpwc=0 combination is itself under attacker or hypervisor control.\nPR:L - Access to /dev/iommu plus a VFIO device fd is required, which in standard device-assignment deployments is delegated to the unprivileged VMM user (qemu/libvirt) rather than requiring real root. A compromised VMM process or a user in a device-assignment group can drive the entire sequence.\nUI:N - The full sequence — hwpt allocation, dirty-tracking enable, and the subsequent device DMA — is driven entirely by the attacker's own process and the device it already controls. No victim action is needed.\nS:C - The defect is in the IOMMU's own DMA-isolation enforcement: SSADE is programmed on hardware that cannot coherently update paging-structure entries, and the unflushed cached RMW in intel_iommu_read_and_clear_dirty() can resurrect stale second-stage PTEs. An assigned device's DMA then reaches memory outside its authorized translation, crossing the IOMMU security boundary.\nC:H - Stale or incorrectly-updated second-stage paging entries leave a device-visible mapping to host pages that have been unmapped and potentially reassigned, giving the controlled device DMA reads of arbitrary host memory. Dirty-bitmap results are also unreliable, leaking incorrect state across a migration boundary.\nI:H - The same stale-translation window gives the assigned device DMA writes into host memory outside its mapping — an arbitrary write primitive from the device side that defeats IOMMU containment. Silently missed dirty pages additionally corrupt guest memory state on live migration.\nA:H - The VT-d specification mandates a non-recoverable fault whenever the hardware must atomically update A/EA/D bits in a non-snooped paging-structure entry, so the assigned device's DMA is blocked outright and the DMAR fault handler is driven repeatedly. The device and any VM depending on it are rendered inoperable."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/iommu/intel/iommu.h"],"versions":[{"version":"f35f22cc760eb2c7034bf53251399685d611e03f","lessThan":"ebe16d245a00626bb87163862a1b07daf5475a3e","status":"affected","versionType":"git"},{"version":"f35f22cc760eb2c7034bf53251399685d611e03f","lessThan":"8d096ce0e87bdc361f0b25d7943543bc53aa0b9e","status":"affected","versionType":"git"},{"version":"f35f22cc760eb2c7034bf53251399685d611e03f","lessThan":"57f55048e564dedd8a4546d018e29d6bbfff0a7e","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/iommu.h"],"versions":[{"version":"6.7","status":"affected"},{"version":"0","lessThan":"6.7","status":"unaffected","versionType":"semver"},{"version":"6.12.53","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.17.3","lessThanOrEqual":"6.17.*","status":"unaffected","versionType":"semver"},{"version":"6.18","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":"6.7","versionEndExcluding":"6.12.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.17.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ebe16d245a00626bb87163862a1b07daf5475a3e"},{"url":"https://git.kernel.org/stable/c/8d096ce0e87bdc361f0b25d7943543bc53aa0b9e"},{"url":"https://git.kernel.org/stable/c/57f55048e564dedd8a4546d018e29d6bbfff0a7e"}],"title":"iommu/vt-d: Disallow dirty tracking if incoherent page walk","x_generator":{"engine":"bippy-1.2.0"}}}}