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CVE-2026-64324 (GCVE-0-2026-64324)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-08-17 04:53
VLAI
Title
udf: validate free block extents against the partition length
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.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 934f815345c09c290a9b9a9cfdddc203ec2117e8 , < fdd6229d2ae9914c1f25d1041db0f4f312a4fa76 (git)
Affected: 22cc7323f090646c8cfb5939e6f15bdc2ed3fd27 , < b54aee5652fcd7c23a0904a4623ec462c3edc70c (git)
Affected: 7c4fa9ebfce69619d132fe703dc2e2cf62a13723 , < 12af328d2ee8d68e81ba612246d0b54b22d23e1f (git)
Affected: 5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3 , < fb49099206c5c57af28a157249fa7bcb5518f99e (git)
Affected: 56e69e59751d20993f243fb7dd6991c4e522424c , < 9442d75429b0c556292a7454fe888d54259f5240 (git)
Affected: 56e69e59751d20993f243fb7dd6991c4e522424c , < 335202ab25b01fdd45889ff25eab70864686dea3 (git)
Affected: 56e69e59751d20993f243fb7dd6991c4e522424c , < be87de7789a82a030a4896bc7683415ec9fa6f2b (git)
Affected: 56e69e59751d20993f243fb7dd6991c4e522424c , < 5f0419457f89dce1a3f1c8e62a3adf2f39ab8168 (git)
Affected: 097420e48e30f51e8f4f650b5c946f5af63ec1a3 (git)
Affected: 5def895b42ef16a2da6402818cba8d7ec8ede1ef (git)
Affected: 05fb2bf477d3fe5421bd4cb699574737f52bd88b (git)
Affected: 5.10.224 , < 5.10.261 (semver)
Affected: 5.15.165 , < 5.15.212 (semver)
Affected: 6.1.105 , < 6.1.178 (semver)
Affected: 6.6.46 , < 6.6.145 (semver)
Affected: 4.19.320 , < 4.20 (semver)
Affected: 5.4.282 , < 5.5 (semver)
Affected: 6.10.5 , < 6.11 (semver)
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Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.96 , ≤ 6.12.* (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "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."
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            }
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        "dateUpdated": "2026-08-17T04:53:26.109Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76"
        },
        {
          "url": "https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c"
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        {
          "url": "https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168"
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      ],
      "title": "udf: validate free block extents against the partition length",
      "x_generator": {
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      }
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    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64324",
    "datePublished": "2026-07-25T08:49:52.063Z",
    "dateReserved": "2026-07-19T15:36:31.780Z",
    "dateUpdated": "2026-08-17T04:53:26.109Z",
    "state": "PUBLISHED"
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    "epss": {
      "cve": "CVE-2026-64324",
      "date": "2026-09-20",
      "epss": "0.0016",
      "percentile": "0.0565"
    },
    "microsoft_vex": {
      "current_release_date": "2026-07-27T14:47:53.000Z",
      "cve": "CVE-2026-64324",
      "id": "msrc_CVE-2026-64324",
      "initial_release_date": "2026-07-26T01:05:37.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "udf: validate free block extents against the partition length",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64324.json",
      "version": "2"
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                    "version": "7.2",
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                ]
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            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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        "configurations": [
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        ],
        "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": "2026-09-04T14:51:53.050",
        "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",
            "tags": [
              "Patch"
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            "url": "https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f"
          },
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            "url": "https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240"
          },
          {
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            "tags": [
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          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
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            "url": "https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b"
          },
          {
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            "tags": [
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            "url": "https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e"
          },
          {
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            "tags": [
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            "url": "https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-129"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-19T17:54:29+00:00",
      "cve": "CVE-2026-64324",
      "id": "CVE-2026-64324",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:known_affected": "90",
      "product_status:known_not_affected": "184",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: udf: validate free block extents against the partition length",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64324.json",
      "version": "3"
    }
  }
}



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Taxonomy of the tags.





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.

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.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.