Vulnerability-Lookup

FKIE_CVE-2026-97991

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 15:18

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Summary

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.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vdpa/vdpa_sim/vdpa_sim_blk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "14acb0d44b7d90a077beb7b92b444b90bafda9d9",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            },
            {
              "lessThan": "a8a1413a2cfdbedc896249f461d6d92efbbfe21f",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            },
            {
              "lessThan": "d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            },
            {
              "lessThan": "0a8693f00c408d85f086ad85d29e7030bf1e2055",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vdpa/vdpa_sim/vdpa_sim_blk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "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-\u003ebuffer + 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-\u003ebuffer + 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-\u003ebuffer + 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."
    }
  ],
  "id": "CVE-2026-97991",
  "lastModified": "2026-09-25T15:18:03.453",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.1,
        "impactScore": 6.0,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-25T11:17:27.220",
  "references": [
    {
      "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/a8a1413a2cfdbedc896249f461d6d92efbbfe21f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-97991 (GCVE-0-2026-97991)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:23 – Updated: 2026-09-25 14:41

Title

vdpa_sim_blk: reject out-of-range sector starts

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/14acb0d44b7d90a07…
https://git.kernel.org/stable/c/a8a1413a2cfdbedc8…
https://git.kernel.org/stable/c/d6dac17e20fd2abd0…
https://git.kernel.org/stable/c/0a8693f00c408d85f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 7d189f617f83f780915b737896a696ff605bd19f , < 14acb0d44b7d90a077beb7b92b444b90bafda9d9 (git) Affected: 7d189f617f83f780915b737896a696ff605bd19f , < a8a1413a2cfdbedc896249f461d6d92efbbfe21f (git) Affected: 7d189f617f83f780915b737896a696ff605bd19f , < d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf (git) Affected: 7d189f617f83f780915b737896a696ff605bd19f , < 0a8693f00c408d85f086ad85d29e7030bf1e2055 (git)
Linux	Linux	Affected: 5.13 Unaffected: 0 , < 5.13 (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vdpa/vdpa_sim/vdpa_sim_blk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "14acb0d44b7d90a077beb7b92b444b90bafda9d9",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            },
            {
              "lessThan": "a8a1413a2cfdbedc896249f461d6d92efbbfe21f",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            },
            {
              "lessThan": "d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            },
            {
              "lessThan": "0a8693f00c408d85f086ad85d29e7030bf1e2055",
              "status": "affected",
              "version": "7d189f617f83f780915b737896a696ff605bd19f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vdpa/vdpa_sim/vdpa_sim_blk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc3",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003ebuffer + 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-\u003ebuffer + 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-\u003ebuffer + 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bad value is virtio_blk_outhdr.sector, written into the virtqueue by the virtio driver. That driver is a guest VM using the device through vhost-vdpa, or a local process with access to /dev/vhost-vdpa-N. vdpasim_blk_handle_req() reads it with vringh_getdesc_iotlb()/vringh_iov_pull_iotlb(). No network protocol carries it.\nAC:H - The code needs a vdpa_sim_blk device, a test simulator that root must create with VDPA_CMD_DEV_NEW (GENL_ADMIN_PERM) and bind to vhost-vdpa for a VM. The attacker cannot set that up. Once it exists, a single request with a large sector fires the bug every time.\nPR:L - The attacker needs control of the virtqueue driver, for example the guest kernel of a VM that was given the device, or a user granted the vhost-vdpa char device. That is ordinary tenant privilege, not host root.\nUI:N - Once the device is assigned, the attacker posts the request on their own virtqueue and the simulator\u0027s work function runs vdpasim_blk_handle_req() with no host-side action.\nS:C - The driver of the device (usually a guest VM) corrupts or reads host kernel memory outside blk-\u003ebuffer. That crosses from the guest\u0027s authority into the host kernel\u0027s, a guest-to-host boundary.\nC:H - VIRTIO_BLK_T_IN with an out-of-range sector makes vringh_iov_push_iotlb() copy from blk-\u003ebuffer + (sector \u003c\u003c 9). The attacker picks that offset from the kvzalloc buffer, and the host kernel memory is returned into the attacker\u0027s own descriptors.\nI:H - VIRTIO_BLK_T_OUT makes vringh_iov_pull_iotlb() copy attacker data to blk-\u003ebuffer + offset, and WRITE_ZEROES memsets there. The offset is under attacker control, which gives a write into host kernel memory that can lead to code execution.\nA:H - A write or read at a wild offset hits unmapped or critical host memory and oopses or panics the host kernel. That also takes down every other VM on the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:41:48.545Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9"
        },
        {
          "url": "https://git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f"
        },
        {
          "url": "https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf"
        },
        {
          "url": "https://git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055"
        }
      ],
      "title": "vdpa_sim_blk: reject out-of-range sector starts",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97991",
    "datePublished": "2026-09-25T10:23:23.863Z",
    "dateReserved": "2026-09-25T10:18:58.209Z",
    "dateUpdated": "2026-09-25T14:41:48.545Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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FKIE_CVE-2026-97991

CVE-2026-97991 (GCVE-0-2026-97991)

Tags

Sightings

Nomenclature

Related by attack behaviour