CVE-2026-64324 (GCVE-0-2026-64324)
Vulnerability from cvelistv5
Published
2026-07-25 08:49
Modified
2026-08-17 04:53
Severity ?
VLAI Severity ?
EPSS score ?
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 |
Version: 934f815345c09c290a9b9a9cfdddc203ec2117e8 Version: 22cc7323f090646c8cfb5939e6f15bdc2ed3fd27 Version: 7c4fa9ebfce69619d132fe703dc2e2cf62a13723 Version: 5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3 Version: 56e69e59751d20993f243fb7dd6991c4e522424c Version: 56e69e59751d20993f243fb7dd6991c4e522424c Version: 56e69e59751d20993f243fb7dd6991c4e522424c Version: 56e69e59751d20993f243fb7dd6991c4e522424c Version: 097420e48e30f51e8f4f650b5c946f5af63ec1a3 Version: 5def895b42ef16a2da6402818cba8d7ec8ede1ef Version: 05fb2bf477d3fe5421bd4cb699574737f52bd88b Version: 5.10.224 ≤ Version: 5.15.165 ≤ Version: 6.1.105 ≤ Version: 6.6.46 ≤ Version: 4.19.320 ≤ Version: 5.4.282 ≤ Version: 6.10.5 ≤ |
||
{
"containers": {
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"status": "affected",
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{
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"status": "affected",
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{
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{
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{
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],
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},
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},
{
"lessThanOrEqual": "6.1.*",
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},
{
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{
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"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"vulnerable": true
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{
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{
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{
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{
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{
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{
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The flaw is reached through a local ftruncate(2) on a crafted, mounted UDF filesystem; no network protocol reaches this path.\nAC:L - The attacker controls the malicious extent and truncation offset, and a single ftruncate(2) reliably triggers the fault without a race or uncontrollable condition.\nPR:L - UDF cannot be mounted through an unprivileged user namespace, but default [UDisks policy](https://storaged.org/doc/udisks2-api/latest/udisks-polkit-ac tions.html) permits an active unprivileged user to mount removable media without administrator authentication.\nUI:N - The attacking local user can mount the supplied removable filesystem and truncate its writable file directly; no separate victim action is required.\nS:U - The vulnerable UDF code and the affected kernel resources remain within the host kernel\u0027s security authority; ordinary kernel privilege escalation does not change scope.\nC:H - Although the reproduced path is an out-of-bounds pointer-slot read followed by panic, a zero-valued out-of-range slot causes read_block_bitmap() to write a buffer_head pointer through that attacker-selected slot. Under the required higher-severity rule, this exploitable kernel heap corruption can enable code execution and unrestricted disclosure.\nI:H - The conditional out-of-bounds buffer_head pointer store corrupts kernel heap memory at an attacker-selected array index and can potentially alter control-relevant objects. This supports control-flow hijacking or arbitrary modification under the required higher-severity assumption.\nA:H - The [upstream report](https://lkml.iu.edu/2605.1/15216.html) confirms that one ftruncate(2) reliably panics the kernel, causing complete system unavailability."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:53:26.109Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76"
},
{
"url": "https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c"
},
{
"url": "https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f"
},
{
"url": "https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e"
},
{
"url": "https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240"
},
{
"url": "https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3"
},
{
"url": "https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b"
},
{
"url": "https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168"
}
],
"title": "udf: validate free block extents against the partition length",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"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"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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