CVE-2026-89584 (GCVE-0-2026-89584)
Vulnerability from cvelistv5
Published
2026-09-11 19:44
Modified
2026-10-19 08:49
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: block: validate user space vectors during extraction The bio-based drivers don't necessarily check the alignment split, and stacking block drivers don't always handle a misalignment detected after submitting the bio. Validate user vectors against the device's dma_alignment as the bio is built from the iov_iter, rejecting misaligned early with -EINVAL.
References
Impacted products
Vendor Product Version
Linux Linux Version: 5ff3f74e145adc79b49668adb8de276446acf6be
Version: 5ff3f74e145adc79b49668adb8de276446acf6be
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/bio.c",
            "block/blk-map.c",
            "block/fops.c",
            "fs/iomap/direct-io.c",
            "include/linux/bio.h",
            "include/linux/uio.h",
            "lib/iov_iter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d44a97a3b1c00cc571245124e23e5ceb0a0225a0",
              "status": "affected",
              "version": "5ff3f74e145adc79b49668adb8de276446acf6be",
              "versionType": "git"
            },
            {
              "lessThan": "14b007e178811db72fbb1ebb3535160db6ec1e6a",
              "status": "affected",
              "version": "5ff3f74e145adc79b49668adb8de276446acf6be",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "block/bio.c",
            "block/blk-map.c",
            "block/fops.c",
            "fs/iomap/direct-io.c",
            "include/linux/bio.h",
            "include/linux/uio.h",
            "lib/iov_iter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "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": "7.2.4",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: validate user space vectors during extraction\n\nThe bio-based drivers don\u0027t necessarily check the alignment split, and\nstacking block drivers don\u0027t always handle a misalignment detected after\nsubmitting the bio. Validate user vectors against the device\u0027s\ndma_alignment as the bio is built from the iov_iter, rejecting\nmisaligned early with -EINVAL."
        }
      ],
      "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 - Missing dma_alignment validation is in bio_iov_iter_get_pages()/iov_iter_extract_bvecs(), reached only via local O_DIRECT (preadv/pwritev/io_uring) through blkdev_direct_IO() and iomap_dio_bio_iter_one() on ext4/XFS/btrfs/f2fs or raw block devices; ksmbd/nfsd do not feed attacker-controlled user iovecs into this path.\nAC:L - After the simplified DIO checks, only file offset and total length must be logical-block aligned; the attacker fully controls each iovec address and length and can submit misaligned buffers or io_uring registered buffers deterministically, with no race or attacker-uncontrolled layout required.\nPR:L - Any unprivileged user with read or write access to a regular file on an iomap DIO filesystem, or to a block device they can open, can issue O_DIRECT with no capability; stacked dm/md/LUKS setups are a deployment precondition, not a privilege the attacker must obtain.\nUI:N - The attacker opens their own file or device and issues the misaligned O_DIRECT I/O themselves; no separate victim must mount media, confirm a prompt, or otherwise participate.\nS:U - Impact stays inside the host kernel block layer and stacked devices (invalid DMA, driver mishandling, array denial of service) and does not cross a VM, hypervisor, IOMMU, or sandbox boundary.\nC:H - Bio-based drivers (dm, md) skip __bio_split_to_limits() on normal I/O, so attacker-controlled bvec offsets reach DMA and crypto SG lists such as dm-crypt sg_set_page(). Unaligned or page-crossing DMA, including non-coherent cache-line effects and hardware address rounding, can read adjacent memory.\nI:H - The same unvalidated user vectors are programmed into device DMA and driver scatterlists; misaligned writes, hardware address masking, and cache-line tearing on non-coherent DMA can corrupt adjacent memory or neighboring disk blocks, and drivers that assume aligned bvecs can perform out-of-bounds writes.\nA:H - Misaligned bios are known to degrade md/raid1 and dm-mirror arrays when lower devices return BLK_STS_INVAL, hang dm-io on byte-granular fragments, and can oops or hang bio-based drivers and DMA engines that reject unaligned segments, all kernel-level availability failures."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:49:17.054Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d44a97a3b1c00cc571245124e23e5ceb0a0225a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/14b007e178811db72fbb1ebb3535160db6ec1e6a"
        }
      ],
      "title": "block: validate user space vectors during extraction",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89584",
    "datePublished": "2026-09-11T19:44:49.838Z",
    "dateReserved": "2026-09-11T19:38:34.729Z",
    "dateUpdated": "2026-10-19T08:49:17.054Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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