{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90387", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.809Z", "datePublished": "2026-09-17T16:09:22.493Z", "dateUpdated": "2026-10-19T09:02:50.001Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:02:50.001Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nswiotlb: Preserve allocation virtual address for dynamic pools\n\nswiotlb_alloc_tlb() can allocate from the DMA atomic pool when a decrypted\npool is needed from atomic context. With CONFIG_DMA_DIRECT_REMAP, the\natomic pool is backed by remapped virtual addresses, which are not the same\nas the direct-map addresses returned by phys_to_virt().\n\nswiotlb_init_io_tlb_pool() currently reconstructs the pool virtual address\nfrom the physical start address. For atomic-pool backed allocations this\nstores the wrong address in pool->vaddr. Later, swiotlb_free_tlb() passes\nthat address to dma_free_from_pool(), which will fail to recognize the\nchunk\n\nPass the virtual address returned by the allocation path into\nswiotlb_init_io_tlb_pool(), and store that address in pool->vaddr. This\nkeeps the pool free path using the same virtual address as the allocator." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The mismatch is kernel-internal: swiotlb_init_io_tlb_pool() stored phys_to_virt(start) instead of the remapped cpu_addr from dma_alloc_from_pool(), not bytes from a protocol message. Local I/O reaches it via dma_map_page_attrs() → dma_direct_map_phys() → swiotlb_map() → swiotlb_tbl_map_single() → swiotlb_find_slots() GFP_NOWAIT transient allocation.\nAC:L - On an ARM64 realm guest force_dma_unencrypted() is true, so every GFP_NOWAIT swiotlb_alloc_tlb() in swiotlb_find_slots() uses dma_alloc_from_pool() and CONFIG_DMA_DIRECT_REMAP makes that vaddr differ from phys_to_virt(); filling io_tlb_default_mem then unmapping is attacker-driven I/O with no race.\nPR:L - No capability check gates dma_map_page_attrs() or swiotlb_tbl_map_single(). An unprivileged user triggers the GFP_NOWAIT transient pool by ordinary I/O, e.g. virtio-blk virtqueue_add_sgs() → virtqueue_map_page_attrs(), or sendmsg on virtio-net, which bounce through SWIOTLB_FORCE on a CCA guest.\nUI:N - The attacker’s own map/unmap I/O allocates the transient pool and later dma_direct_unmap_phys() → __swiotlb_tbl_unmap_single() → swiotlb_del_transient() → swiotlb_dyn_free() → swiotlb_free_tlb(); no victim mount or other action is required.\nS:U - pool->start remains page_to_phys(tlb), so the device still DMAs to the allocated bounce pages. The defect is swiotlb_free_tlb() passing the linear phys_to_virt address into dma_free_from_pool()/__free_pages, corrupting the guest page allocator, not an IOMMU map of foreign pages or a realm/host escape.\nC:H - When dma_free_from_pool() rejects the linear address, swiotlb_free_tlb() still __free_pages()s those atomic-pool frames while gen_pool still owns them and dma_common_contiguous_remap() leaves a decrypted VM_DMA_COHERENT alias, so the pages can be reallocated with a stale kernel mapping.\nI:H - atomic_pool_expand() allocated one high-order compound page that gen_pool carved up; __free_pages(virt_to_page(linear_vaddr), get_order(tlb_size)) is a wrong-order or tail-page free of that block, corrupting buddy metadata and yielding an arbitrary write primitive.\nA:H - The same __free_pages() of a compound tail page or the wrong order produces bad-page handling, VM_BUG, or an oops, and any leftover coherent remap or reused frame later panics when touched." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/dma/swiotlb.c" ], "versions": [ { "version": "79636caad3618e2b38457f6e298c9b31ba82b489", "lessThan": "68bf3ebd8e7020dae58e8aa14c7d482738bff9a8", "status": "affected", "versionType": "git" }, { "version": "79636caad3618e2b38457f6e298c9b31ba82b489", "lessThan": "45507dcb0847e96add4455274b12df0eca6590b4", "status": "affected", "versionType": "git" }, { "version": "79636caad3618e2b38457f6e298c9b31ba82b489", "lessThan": "35e0103177826430b5df888b1506239d41e76ab5", "status": "affected", "versionType": "git" }, { "version": "79636caad3618e2b38457f6e298c9b31ba82b489", "lessThan": "c1f4d7763cdf1b9e0d35c14aa6f52d0512a36319", "status": "affected", "versionType": "git" }, { "version": "79636caad3618e2b38457f6e298c9b31ba82b489", "lessThan": "57d29044d0f29a76c6ec0c112c8c7371d5608dc7", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/dma/swiotlb.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "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": "6.6", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/68bf3ebd8e7020dae58e8aa14c7d482738bff9a8" }, { "url": "https://git.kernel.org/stable/c/45507dcb0847e96add4455274b12df0eca6590b4" }, { "url": "https://git.kernel.org/stable/c/35e0103177826430b5df888b1506239d41e76ab5" }, { "url": "https://git.kernel.org/stable/c/c1f4d7763cdf1b9e0d35c14aa6f52d0512a36319" }, { "url": "https://git.kernel.org/stable/c/57d29044d0f29a76c6ec0c112c8c7371d5608dc7" } ], "title": "swiotlb: Preserve allocation virtual address for dynamic pools", "x_generator": { "engine": "bippy-1.2.0" } } } }