CVE-2026-90387 (GCVE-0-2026-90387)
Vulnerability from cvelistv5
Published
2026-09-17 16:09
Modified
2026-10-19 09:02
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: swiotlb: Preserve allocation virtual address for dynamic pools swiotlb_alloc_tlb() can allocate from the DMA atomic pool when a decrypted pool is needed from atomic context. With CONFIG_DMA_DIRECT_REMAP, the atomic pool is backed by remapped virtual addresses, which are not the same as the direct-map addresses returned by phys_to_virt(). swiotlb_init_io_tlb_pool() currently reconstructs the pool virtual address from the physical start address. For atomic-pool backed allocations this stores the wrong address in pool->vaddr. Later, swiotlb_free_tlb() passes that address to dma_free_from_pool(), which will fail to recognize the chunk Pass the virtual address returned by the allocation path into swiotlb_init_io_tlb_pool(), and store that address in pool->vaddr. This keeps the pool free path using the same virtual address as the allocator.
References
Impacted products
Vendor Product Version
Linux Linux Version: 79636caad3618e2b38457f6e298c9b31ba82b489
Version: 79636caad3618e2b38457f6e298c9b31ba82b489
Version: 79636caad3618e2b38457f6e298c9b31ba82b489
Version: 79636caad3618e2b38457f6e298c9b31ba82b489
Version: 79636caad3618e2b38457f6e298c9b31ba82b489
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/dma/swiotlb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
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            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "c1f4d7763cdf1b9e0d35c14aa6f52d0512a36319",
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              "versionType": "git"
            },
            {
              "lessThan": "57d29044d0f29a76c6ec0c112c8c7371d5608dc7",
              "status": "affected",
              "version": "79636caad3618e2b38457f6e298c9b31ba82b489",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/dma/swiotlb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003evaddr. 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-\u003evaddr. This\nkeeps the pool free path using the same virtual address as the allocator."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "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() \u2192 dma_direct_map_phys() \u2192 swiotlb_map() \u2192 swiotlb_tbl_map_single() \u2192 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() \u2192 virtqueue_map_page_attrs(), or sendmsg on virtio-net, which bounce through SWIOTLB_FORCE on a CCA guest.\nUI:N - The attacker\u2019s own map/unmap I/O allocates the transient pool and later dma_direct_unmap_phys() \u2192 __swiotlb_tbl_unmap_single() \u2192 swiotlb_del_transient() \u2192 swiotlb_dyn_free() \u2192 swiotlb_free_tlb(); no victim mount or other action is required.\nS:U - pool-\u003estart 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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:02:50.001Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "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"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90387",
    "datePublished": "2026-09-17T16:09:22.493Z",
    "dateReserved": "2026-09-11T19:38:34.809Z",
    "dateUpdated": "2026-10-19T09:02:50.001Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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