CVE-2026-72492 (GCVE-0-2026-72492)
Vulnerability from cvelistv5
Published
2026-08-15 05:57
Modified
2026-08-17 05:44
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free in same_client_has_lease()
same_client_has_lease() returns an opinfo pointer from ci->m_op_list
after dropping ci->m_lock without taking a reference.
smb_grant_oplock() then dereferences that pointer in copy_lease() and
when checking breaking_cnt. A concurrent close can remove the old lease
from ci->m_op_list and drop the last reference before the caller uses
the returned pointer, leading to a use-after-free.
Take a reference when same_client_has_lease() selects an existing lease,
drop any previous match while scanning, and release the returned
reference in smb_grant_oplock() after copying the lease state.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 |
||
{
"containers": {
"cna": {
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{
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"product": "Linux",
"programFiles": [
"fs/smb/server/oplock.c"
],
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"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "5.15"
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{
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"status": "unaffected",
"version": "0",
"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": [
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"versionEndExcluding": "5.15.212",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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\nksmbd: fix use-after-free in same_client_has_lease()\n\nsame_client_has_lease() returns an opinfo pointer from ci-\u003em_op_list\nafter dropping ci-\u003em_lock without taking a reference.\n\nsmb_grant_oplock() then dereferences that pointer in copy_lease() and\nwhen checking breaking_cnt. A concurrent close can remove the old lease\nfrom ci-\u003em_op_list and drop the last reference before the caller uses\nthe returned pointer, leading to a use-after-free.\n\nTake a reference when same_client_has_lease() selects an existing lease,\ndrop any previous match while scanning, and release the returned\nreference in smb_grant_oplock() after copying the lease state."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - ksmbd is the in-kernel SMB server on TCP/445; the UAF is reached when a remote client sends SMB2_CREATE with a lease context, handled via ksmbd_conn_handler_loop() through smb2_open() and smb_grant_oplock() into same_client_has_lease().\nAC:L - The attacker controls both sides of the race by holding a leased open on one SMB connection while concurrently issuing SMB2_CREATE (lease upgrade) and SMB2_CLOSE on another connection or channel; no victim-dependent timing or memory layout is required.\nPR:L - Exploitation requires a valid SMB2 session, tree connect, and share permission to open/close the target file with SMB3 leasing enabled; smb2_check_user_session() rejects SMB2_CREATE without SMB2_SESSION_VALID, so this is not reachable on pre-authentication negotiate/echo paths.\nUI:N - No victim interaction is required; the attacker drives all SMB2_CREATE and SMB2_CLOSE operations on their own client connection(s) to trigger the concurrent lease lookup and file close.\nS:U - Impact is kernel heap corruption and privilege escalation on the SMB server host within the ksmbd/kernel security authority; it does not cross a VM, container, or IOMMU boundary.\nC:H - Use-after-free of a freed oplock_info/lease object in copy_lease() reads attacker-influenced slab contents (level, lease state, keys, flags, epoch), enabling kernel memory disclosure and arbitrary-read primitive construction.\nI:H - The UAF dereferences freed oplock_info and embedded lease pointers during copy_lease() and breaking_cnt checks, enabling heap grooming and memory corruption exploitable for arbitrary write or control-flow hijack as root.\nA:H - Concurrent close can free the oplock_info before smb_grant_oplock() uses it, causing reliable kernel memory corruption, oops, or panic and repeatable remote denial of service against the server."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:44:53.329Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/aaa3bb2bbf2ccbfea9e4e0b9dabf3afc60b50cd0"
},
{
"url": "https://git.kernel.org/stable/c/09634cd055d9bd8dd167995ea52bcd8028dd5dac"
},
{
"url": "https://git.kernel.org/stable/c/7c3264d273d524aa6adcce23c01087271f13586f"
},
{
"url": "https://git.kernel.org/stable/c/79c7c59bb519db6f5a2a151965e825ec725614cc"
},
{
"url": "https://git.kernel.org/stable/c/35d3d6ff2bc1e7aaecb15d5377ebbd6227acae0d"
},
{
"url": "https://git.kernel.org/stable/c/0ff82a9cf9312678d8bc4edeef0b6e82659ac12a"
},
{
"url": "https://git.kernel.org/stable/c/65b655f65c3ca1ab5d598d3832bb0ff531725858"
}
],
"title": "ksmbd: fix use-after-free in same_client_has_lease()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72492",
"datePublished": "2026-08-15T05:57:26.967Z",
"dateReserved": "2026-08-09T03:40:39.936Z",
"dateUpdated": "2026-08-17T05:44:53.329Z",
"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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