CVE-2026-68098 (GCVE-0-2026-68098)
Vulnerability from cvelistv5
Published
2026-08-10 11:58
Modified
2026-08-17 04:58
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: bound DACL dedup walk to copied ACEs
set_ntacl_dacl() can stop copying ACEs before consuming the full input
DACL when size accounting overflows.
When that happens, num_aces reflects only the ACEs that were actually
copied into the output DACL, but set_posix_acl_entries_dacl() still
receives nt_num_aces and uses it to walk the existing ACE array during
dedup.
That makes the dedup walk scan past the copied ACE array and inspect
buffer tail that does not contain valid ACEs.
Split the two meanings currently carried by the NT ACE count. Pass the
number of copied NT ACEs to bound the dedup walk, and preserve the
original "input DACL had NT ACEs" state separately for the
Everyone/default ACL fallback.
This keeps the dedup walk aligned with the ACEs that are actually
present in the rebuilt DACL.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/server/smbacl.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "b057a851129c6a084e7e393b62ca3abf6c2660bc",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "f1eba60db813ec28732bf18b5f0a67ebac9c3100",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "a0ebdaa79e10210d4e8ed9fe138e8f4d569719e3",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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{
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"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/smb/server/smbacl.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"lessThan": "5.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"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": "6.6.148",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.101",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.42",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.6",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "5.15",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: bound DACL dedup walk to copied ACEs\n\nset_ntacl_dacl() can stop copying ACEs before consuming the full input\nDACL when size accounting overflows.\n\nWhen that happens, num_aces reflects only the ACEs that were actually\ncopied into the output DACL, but set_posix_acl_entries_dacl() still\nreceives nt_num_aces and uses it to walk the existing ACE array during\ndedup.\n\nThat makes the dedup walk scan past the copied ACE array and inspect\nbuffer tail that does not contain valid ACEs.\n\nSplit the two meanings currently carried by the NT ACE count. Pass the\nnumber of copied NT ACEs to bound the dedup walk, and preserve the\noriginal \"input DACL had NT ACEs\" state separately for the\nEveryone/default ACL fallback.\n\nThis keeps the dedup walk aligned with the ACEs that are actually\npresent in the rebuilt DACL."
}
],
"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 - The flaw is in ksmbd\u0027s in-kernel SMB server (fs/smb/server/smbacl.c), triggered when a remote client sends SMB2 QUERY_INFO (security descriptor) over TCP/445; build_sec_desc() reads the attacker\u0027s stored NTACL xattr and calls set_ntacl_dacl().\nAC:L - An authenticated attacker fully controls the crafted DACL planted via SMB2 SET_INFO and can deterministically trigger partial ACE copy (size overflow) then QUERY_INFO; no race or victim-dependent state is required beyond a file with POSIX ACLs on an ACL-xattr-enabled share.\nPR:L - Exploitation requires a completed SMB2 session and tree connect; planting the malicious security.NTACL xattr needs FILE_WRITE_DAC via SMB2 SET_INFO, and triggering needs an open file handle for QUERY_INFO\u2014standard low-privileged share access, not host root.\nUI:N - The server processes the attacker\u0027s SMB2 SET_INFO and QUERY_INFO requests automatically in ksmbd worker threads; no separate local user or administrator action is required beyond normal server operation.\nS:U - Impact is confined to kernel heap memory corruption and ACL processing within the ksmbd server context; it does not cross VM, container, or IOMMU security boundaries.\nC:H - The dedup walk scans past copied ACEs into buffer tail without valid ACE structures, performing out-of-bounds reads including ntace-\u003esid.sub_auth[ntace-\u003esid.num_subauth-1] on attacker-influenced data; per kernel guidance OOB reads score High.\nI:H - Out-of-bounds kernel heap access during the unbounded ACE walk is a memory corruption primitive; incorrect dedup can also append extra ACEs to the rebuilt security descriptor, enabling integrity impact beyond a simple crash.\nA:H - Walking invalid ACE headers (e.g., zero size fields) can hang the dedup loop, and out-of-bounds reads of invalid sid fields can kernel oops/panic, denying SMB service on the affected host."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:58:46.978Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/6d9d7aa4a2c99c31acfa28921c30b684110cf66c"
},
{
"url": "https://git.kernel.org/stable/c/b057a851129c6a084e7e393b62ca3abf6c2660bc"
},
{
"url": "https://git.kernel.org/stable/c/f1eba60db813ec28732bf18b5f0a67ebac9c3100"
},
{
"url": "https://git.kernel.org/stable/c/a0ebdaa79e10210d4e8ed9fe138e8f4d569719e3"
},
{
"url": "https://git.kernel.org/stable/c/58d97fcd0bf1aee694e244cc28635b9df95b543b"
}
],
"title": "ksmbd: bound DACL dedup walk to copied ACEs",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68098",
"datePublished": "2026-08-10T11:58:12.768Z",
"dateReserved": "2026-07-30T09:28:09.368Z",
"dateUpdated": "2026-08-17T04:58:46.978Z",
"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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