FKIE_CVE-2026-64324
Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-09-04 14:51
Severity
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
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 | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * |
{
"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"
},
{
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"status": "affected",
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"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",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
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"matchCriteriaId": "E9C1FD3D-3B79-4FC6-83B1-93C7ADA040CD",
"versionEndExcluding": "4.20",
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},
{
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{
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],
"negate": false,
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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": [
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],
"url": "https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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],
"url": "https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3"
},
{
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},
{
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},
{
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{
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"url": "https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"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"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
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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.
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.
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