CVE-2026-97991

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: vdpa_sim_blk: reject out-of-range sector starts vdpasim_blk_check_range() logs an invalid start sector but continues validating the request. The subsequent unsigned capacity subtraction can underflow and let an out-of-range buffer offset reach the data path. The invalid offset is used by three request paths. VIRTIO_BLK_T_OUT copies guest data to blk->buffer + offset through vringh_iov_pull_iotlb(), causing an out-of-bounds write in _copy_from_iter() or memcpy(). VIRTIO_BLK_T_IN copies from blk->buffer + offset to the guest through vringh_iov_push_iotlb(), causing an out-of-bounds read in _copy_to_iter(). VIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(), causing an out-of-bounds write. Reject starts at or beyond the capacity before the subtraction. Treat the capacity boundary as invalid because the IN and OUT paths round byte counts down to sectors for validation but later copy the original byte counts. A sub-sector request at the capacity boundary would otherwise still access past the end of the buffer. I found this bug myself, though the patch was written with AI assistance.

Severity

HIGH

CVSS score

7.8 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-25 11:17:27.220000

Last modified

2026-10-19 10:17:50.470000

View original CVE JSON

{
  "id": "CVE-2026-97991",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-25T11:17:27.220",
  "lastModified": "2026-10-19T10:17:50.470",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvdpa_sim_blk: reject out-of-range sector starts\n\nvdpasim_blk_check_range() logs an invalid start sector but continues\nvalidating the request.  The subsequent unsigned capacity subtraction can\nunderflow and let an out-of-range buffer offset reach the data path.\n\nThe invalid offset is used by three request paths.  VIRTIO_BLK_T_OUT\ncopies guest data to blk->buffer + offset through\nvringh_iov_pull_iotlb(), causing an out-of-bounds write in\n_copy_from_iter() or memcpy().  VIRTIO_BLK_T_IN copies from\nblk->buffer + offset to the guest through vringh_iov_push_iotlb(),\ncausing an out-of-bounds read in _copy_to_iter().\nVIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(),\ncausing an out-of-bounds write.\n\nReject starts at or beyond the capacity before the subtraction.  Treat the\ncapacity boundary as invalid because the IN and OUT paths round byte counts\ndown to sectors for validation but later copy the original byte counts.  A\nsub-sector request at the capacity boundary would otherwise still access\npast the end of the buffer.\n\nI found this bug myself, though the patch was written with AI assistance."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/vdpa/vdpa_sim/vdpa_sim_blk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "2ff2a8d063fdfa1e1479fb1fe2e3356a2ce89018",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "36ef4d8527f71648f00347f6ba759f0b7e5e0977",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "000c6300776ceaf6b715780113f4275b1be4195b",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "14acb0d44b7d90a077beb7b92b444b90bafda9d9",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "a8a1413a2cfdbedc896249f461d6d92efbbfe21f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "lessThan": "0a8693f00c408d85f086ad85d29e7030bf1e2055",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/vdpa/vdpa_sim/vdpa_sim_blk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "5.13",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "5.13",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.222",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.189",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.158",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.111",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.53",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.7",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "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",
          "attackVector": "LOCAL",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.1,
        "impactScore": 6.0
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/000c6300776ceaf6b715780113f4275b1be4195b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2ff2a8d063fdfa1e1479fb1fe2e3356a2ce89018",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/36ef4d8527f71648f00347f6ba759f0b7e5e0977",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}