FKIE_CVE-2026-64324

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-27 05:16
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: udf: validate free block extents against the partition length udf_free_blocks() checks the logical block number and count against the partition length, but drops the extent offset from that final bound. A crafted extent can pass the guard while logicalBlockNum + offset + count points past the partition, which later indexes past the space bitmap array. A single ftruncate(2) on a file backed by such an extent reliably panics the kernel. This is a local availability issue. On desktop systems where UDisks/polkit allows the active user to mount removable UDF media without CAP_SYS_ADMIN, an unprivileged local user can supply the crafted filesystem and trigger the panic by truncating a writable file on it. Systems that require root or CAP_SYS_ADMIN to mount the image have a higher prerequisite. No confidentiality or integrity impact is claimed: the reproduced primitive is an out-of-bounds read of a bitmap pointer slot followed by a kernel panic. Use the already computed logicalBlockNum + offset + count value for the partition length check. Also make load_block_bitmap() reject an out-of-range block group before indexing s_block_bitmap[], so corrupted callers cannot walk past the flexible array.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/udf/balloc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fdd6229d2ae9914c1f25d1041db0f4f312a4fa76",
              "status": "affected",
              "version": "934f815345c09c290a9b9a9cfdddc203ec2117e8",
              "versionType": "git"
            },
            {
              "lessThan": "b54aee5652fcd7c23a0904a4623ec462c3edc70c",
              "status": "affected",
              "version": "22cc7323f090646c8cfb5939e6f15bdc2ed3fd27",
              "versionType": "git"
            },
            {
              "lessThan": "12af328d2ee8d68e81ba612246d0b54b22d23e1f",
              "status": "affected",
              "version": "7c4fa9ebfce69619d132fe703dc2e2cf62a13723",
              "versionType": "git"
            },
            {
              "lessThan": "fb49099206c5c57af28a157249fa7bcb5518f99e",
              "status": "affected",
              "version": "5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3",
              "versionType": "git"
            },
            {
              "lessThan": "9442d75429b0c556292a7454fe888d54259f5240",
              "status": "affected",
              "version": "56e69e59751d20993f243fb7dd6991c4e522424c",
              "versionType": "git"
            },
            {
              "lessThan": "335202ab25b01fdd45889ff25eab70864686dea3",
              "status": "affected",
              "version": "56e69e59751d20993f243fb7dd6991c4e522424c",
              "versionType": "git"
            },
            {
              "lessThan": "be87de7789a82a030a4896bc7683415ec9fa6f2b",
              "status": "affected",
              "version": "56e69e59751d20993f243fb7dd6991c4e522424c",
              "versionType": "git"
            },
            {
              "lessThan": "5f0419457f89dce1a3f1c8e62a3adf2f39ab8168",
              "status": "affected",
              "version": "56e69e59751d20993f243fb7dd6991c4e522424c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "097420e48e30f51e8f4f650b5c946f5af63ec1a3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5def895b42ef16a2da6402818cba8d7ec8ede1ef",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "05fb2bf477d3fe5421bd4cb699574737f52bd88b",
              "versionType": "git"
            },
            {
              "lessThan": "5.10.261",
              "status": "affected",
              "version": "5.10.224",
              "versionType": "semver"
            },
            {
              "lessThan": "5.15.212",
              "status": "affected",
              "version": "5.15.165",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.178",
              "status": "affected",
              "version": "6.1.105",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.145",
              "status": "affected",
              "version": "6.6.46",
              "versionType": "semver"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.320",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.282",
              "versionType": "semver"
            },
            {
              "lessThan": "6.11",
              "status": "affected",
              "version": "6.10.5",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/udf/balloc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "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\nudf: validate free block extents against the partition length\n\nudf_free_blocks() checks the logical block number and count against the\npartition length, but drops the extent offset from that final bound.  A\ncrafted extent can pass the guard while logicalBlockNum + offset + count\npoints past the partition, which later indexes past the space bitmap\narray.\n\nA single ftruncate(2) on a file backed by such an extent reliably\npanics the kernel.  This is a local availability issue.  On desktop\nsystems where UDisks/polkit allows the active user to mount removable\nUDF media without CAP_SYS_ADMIN, an unprivileged local user can supply\nthe crafted filesystem and trigger the panic by truncating a writable\nfile on it.  Systems that require root or CAP_SYS_ADMIN to mount the\nimage have a higher prerequisite.\n\nNo confidentiality or integrity impact is claimed: the reproduced\nprimitive is an out-of-bounds read of a bitmap pointer slot followed by\na kernel panic.\n\nUse the already computed logicalBlockNum + offset + count value for the\npartition length check.  Also make load_block_bitmap() reject an\nout-of-range block group before indexing s_block_bitmap[], so corrupted\ncallers cannot walk past the flexible array."
    }
  ],
  "id": "CVE-2026-64324",
  "lastModified": "2026-07-27T05:16:42.513",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:13.923",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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