CVE-2026-72310 (GCVE-0-2026-72310)
Vulnerability from cvelistv5
Published
2026-08-15 05:55
Modified
2026-08-17 05:42
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix overflow in passthrough ioctl bounds check
smb2_ioctl_query_info() validates the PASSTHRU_FSCTL response payload
before copying it to userspace.
The payload offset and length both come from 32-bit fields. The bounds
check currently adds OutputOffset and qi.input_buffer_length directly, so
the addition can wrap in 32-bit arithmetic before the result is compared
against the response buffer length.
A malicious server can use a large OutputOffset and a small OutputCount
to make the wrapped sum pass the bounds check. The later copy_to_user()
then reads from io_rsp + OutputOffset, outside the response buffer.
Use size_add() for the offset plus length check so overflow is treated as
out of bounds.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2b1116bbe898aefdf584838448c6869f69851e0f Version: 2005c32ec99ee2490e8131b3953f3f212009ffea Version: 5.4.69 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/client/smb2ops.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "2b1116bbe898aefdf584838448c6869f69851e0f",
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},
{
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},
{
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]
},
{
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"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.5"
},
{
"lessThan": "5.5",
"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": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.261",
"versionStartIncluding": "5.5",
"vulnerable": true
},
{
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{
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{
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{
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},
{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix overflow in passthrough ioctl bounds check\n\nsmb2_ioctl_query_info() validates the PASSTHRU_FSCTL response payload\nbefore copying it to userspace.\n\nThe payload offset and length both come from 32-bit fields. The bounds\ncheck currently adds OutputOffset and qi.input_buffer_length directly, so\nthe addition can wrap in 32-bit arithmetic before the result is compared\nagainst the response buffer length.\n\nA malicious server can use a large OutputOffset and a small OutputCount\nto make the wrapped sum pass the bounds check. The later copy_to_user()\nthen reads from io_rsp + OutputOffset, outside the response buffer.\n\nUse size_add() for the offset plus length check so overflow is treated as\nout of bounds."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.1,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - Exploitation requires processing a crafted SMB2 IOCTL response from a malicious SMB/CIFS server over TCP; the bug is in client-side parsing of attacker-controlled network protocol fields, not in a purely local code path.\nAC:L - A malicious server can reliably supply OutputOffset and OutputCount values that wrap the 32-bit bounds check and pass validation, deterministically triggering the out-of-bounds copy_to_user() without races or special victim state.\nPR:L - The PASSTHRU_FSCTL ioctl path requires CAP_SYS_ADMIN, which an unprivileged local user can obtain inside a user namespace and use to mount CIFS and issue CIFS_QUERY_INFO against an attacker-controlled server.\nUI:N - In the highest-impact scenario the attacker controls the full chain (user-namespace mount plus ioctl) and needs no separate victim action beyond their own exploitation steps.\nS:U - Impact is disclosure of kernel heap memory to the calling userspace process within the same kernel security authority; it does not cross VM, IOMMU, or sandbox boundaries.\nC:H - The integer overflow bypasses bounds checking so copy_to_user() reads qi.input_buffer_length bytes from io_rsp plus attacker-chosen OutputOffset outside the SMB response buffer, leaking adjacent kernel memory to userspace.\nI:N - The flaw is an out-of-bounds kernel read copied to userspace; it does not modify kernel memory, corrupt metadata, or provide a write or code-execution primitive.\nA:H - Reading far outside the allocated SMB response buffer can access unmapped kernel pages during copy_to_user(), causing a kernel fault, oops, or panic in addition to information disclosure."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:42:38.636Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/175357ee0c596cb82054650dfa32fda51ad35aaa"
},
{
"url": "https://git.kernel.org/stable/c/dbd126539c098dba3159ce7d34b10b2daddcbd0f"
},
{
"url": "https://git.kernel.org/stable/c/63feb687e89a3a52a31e6e01764117cc500f1974"
},
{
"url": "https://git.kernel.org/stable/c/160045fc943f6c46b227644261252c8a22b8a87a"
},
{
"url": "https://git.kernel.org/stable/c/b30771b69eafae750afb7385fbcc3d77ed3f3670"
},
{
"url": "https://git.kernel.org/stable/c/1627e7d5c9b09721a141d07cedb178882f1ded67"
},
{
"url": "https://git.kernel.org/stable/c/1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9"
},
{
"url": "https://git.kernel.org/stable/c/a4f27ad055392fa164f5649e89a3637b033c5fcc"
}
],
"title": "smb: client: fix overflow in passthrough ioctl bounds check",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72310",
"datePublished": "2026-08-15T05:55:26.539Z",
"dateReserved": "2026-08-09T03:40:39.918Z",
"dateUpdated": "2026-08-17T05:42:38.636Z",
"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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