{"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"}}}}