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FKIE_CVE-2026-64323

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-09-04 14:52
Severity
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: udf: validate VAT header length against the VAT inode size udf_load_vat() takes the virtual partition's start offset straight from the on-disk VAT 2.0 header without checking it against the VAT inode size: map->s_type_specific.s_virtual.s_start_offset = le16_to_cpu(vat20->lengthHeader); map->s_type_specific.s_virtual.s_num_entries = (sbi->s_vat_inode->i_size - map->s_type_specific.s_virtual.s_start_offset) >> 2; lengthHeader is a fully attacker-controlled 16-bit value. If it exceeds the VAT inode size, the s_num_entries subtraction underflows to a huge count, which defeats the "block > s_num_entries" bound in udf_get_pblock_virt15(); and on the ICB-inline path that function reads ((__le32 *)(iinfo->i_data + s_start_offset))[block] so a large s_start_offset indexes past the inode's in-ICB data. Mounting a crafted UDF image with a virtual (VAT) partition then triggers an out-of-bounds read. Reject a VAT whose header length does not leave room for at least one entry within the VAT inode.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acbPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddadPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/udf/super.c"
          ],
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          "vendor": "Linux",
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "2.6.26"
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              "version": "0",
              "versionType": "semver"
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              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
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          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
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          "negate": false,
          "operator": "OR"
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      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate VAT header length against the VAT inode size\n\nudf_load_vat() takes the virtual partition\u0027s start offset straight from\nthe on-disk VAT 2.0 header without checking it against the VAT inode\nsize:\n\n\tmap-\u003es_type_specific.s_virtual.s_start_offset =\n\t\tle16_to_cpu(vat20-\u003elengthHeader);\n\tmap-\u003es_type_specific.s_virtual.s_num_entries =\n\t\t(sbi-\u003es_vat_inode-\u003ei_size -\n\t\t\tmap-\u003es_type_specific.s_virtual.s_start_offset) \u003e\u003e 2;\n\nlengthHeader is a fully attacker-controlled 16-bit value.  If it exceeds\nthe VAT inode size, the s_num_entries subtraction underflows to a huge\ncount, which defeats the \"block \u003e s_num_entries\" bound in\nudf_get_pblock_virt15(); and on the ICB-inline path that function reads\n\n\t((__le32 *)(iinfo-\u003ei_data + s_start_offset))[block]\n\nso a large s_start_offset indexes past the inode\u0027s in-ICB data.  Mounting\na crafted UDF image with a virtual (VAT) partition then triggers an\nout-of-bounds read.\n\nReject a VAT whose header length does not leave room for at least one\nentry within the VAT inode."
    }
  ],
  "id": "CVE-2026-64323",
  "lastModified": "2026-09-04T14:52:25.060",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:13.790",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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    },
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    },
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    },
    {
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      "url": "https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • 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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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