CVE-2026-97994 (GCVE-0-2026-97994)
Vulnerability from cvelistv5
Published
2026-09-25 10:23
Modified
2026-10-19 09:12
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: vhost/vdpa: reject VRING_NUM larger than device max vhost_vring_set_num() accepts any non-zero power-of-two queue size that fits in 16 bits. vhost-vdpa then passes that value to set_vq_num() without comparing it with get_vq_num_max(). A process with access to /dev/vhost-vdpa-* can therefore configure a queue larger than the device advertises. With vdpa_sim, the worker can walk descriptors beyond the mapped descriptor ring. KASAN reports a 16-byte out-of-bounds read, corresponding to one vring_desc, in the vringh IOTLB path: BUG: KASAN: out-of-bounds in _copy_from_iter Read of size 16 copy_from_iotlb copydesc_iotlb vringh_getdesc_iotlb vdpasim_net_work Cache get_vq_num_max() immediately after reset. Some backends derive it from writable queue-size state, so querying it after SET_NUM may return the current size instead of the device capability. Invalidate the cached value before reset so a failed reset leaves SET_NUM disabled. For VHOST_SET_VRING_NUM, copy the complete vring state once and use the same index and size for validation, vq->num, and set_vq_num(). This ensures that validation and use operate on the same copied values.
References
Impacted products
Vendor Product Version
Linux Linux Version: 4c8cf31885f69e86be0b5b9e6677a26797365e1d
Version: 4c8cf31885f69e86be0b5b9e6677a26797365e1d
Version: 4c8cf31885f69e86be0b5b9e6677a26797365e1d
Version: 4c8cf31885f69e86be0b5b9e6677a26797365e1d
Version: 4c8cf31885f69e86be0b5b9e6677a26797365e1d
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vhost/vdpa.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vhost/vdpa.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
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              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.12.111",
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                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.18.53",
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost/vdpa: reject VRING_NUM larger than device max\n\nvhost_vring_set_num() accepts any non-zero power-of-two queue size that\nfits in 16 bits. vhost-vdpa then passes that value to set_vq_num()\nwithout comparing it with get_vq_num_max().\n\nA process with access to /dev/vhost-vdpa-* can therefore configure a\nqueue larger than the device advertises. With vdpa_sim, the worker can\nwalk descriptors beyond the mapped descriptor ring. KASAN reports a\n16-byte out-of-bounds read, corresponding to one vring_desc, in the\nvringh IOTLB path:\n\n  BUG: KASAN: out-of-bounds in _copy_from_iter\n  Read of size 16\n  copy_from_iotlb\n  copydesc_iotlb\n  vringh_getdesc_iotlb\n  vdpasim_net_work\n\nCache get_vq_num_max() immediately after reset. Some backends derive\nit from writable queue-size state, so querying it after SET_NUM may\nreturn the current size instead of the device capability. Invalidate\nthe cached value before reset so a failed reset leaves SET_NUM\ndisabled.\n\nFor VHOST_SET_VRING_NUM, copy the complete vring state once and use\nthe same index and size for validation, vq-\u003enum, and set_vq_num().\nThis ensures that validation and use operate on the same copied values."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:12:01.173Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4875c65ca53797a0a402fe2bb54d1b12f28b3cda"
        },
        {
          "url": "https://git.kernel.org/stable/c/1d09201d81b7d3e276860cc7b7dbf6c6cbe8e9b4"
        },
        {
          "url": "https://git.kernel.org/stable/c/68232102f20fc961327fb9e0f605a7eaadf030a9"
        },
        {
          "url": "https://git.kernel.org/stable/c/59522639a7d71cff4e20d594d0b9ea30dd0c77e0"
        },
        {
          "url": "https://git.kernel.org/stable/c/ccb1dc7c527f8c925925cf92afc76ae590dac311"
        }
      ],
      "title": "vhost/vdpa: reject VRING_NUM larger than device max",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97994",
    "datePublished": "2026-09-25T10:23:25.719Z",
    "dateReserved": "2026-09-25T10:18:58.209Z",
    "dateUpdated": "2026-10-19T09:12:01.173Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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