FKIE_CVE-2026-72382
Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: reject undersized DACLs before parsing ACEs
parse_dacl() limits the attacker-controlled ACE count by comparing it
with the number of minimal ACEs that fit in the DACL size. The DACL size
field is 16 bits, but the expression subtracts sizeof(struct smb_acl).
Because sizeof() is unsigned, a DACL size smaller than the ACL header
underflows to a large size_t.
A malicious client can reach this with:
SMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY)
-> smb2_set_info_sec()
-> set_info_sec()
-> parse_sec_desc()
-> parse_dacl()
-> init_acl_state(..., 0xffff)
-> init_acl_state(..., 0xffff)
-> kmalloc_objs(..., 0xffff)
Thus a malformed security descriptor can make num_aces pass the guard
and drive large temporary ACL state and pointer-array allocations.
Reject DACLs smaller than struct smb_acl before doing the subtraction,
so the ACE count check cannot be bypassed by the underflow.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"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": [
{
"lessThan": "16fb65ec15fe7c90f50a2115854bfd9a032d4023",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "282847c0cf22f2e961155ac8e42f6eeab7e16049",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "d020e7f27bf65eecd3805404702f716b2b6d9e73",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd",
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"versionType": "git"
},
{
"lessThan": "60908f7ebcd9b6cde74ad5711fab0f49c7970949",
"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": "6.6.145",
"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"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: reject undersized DACLs before parsing ACEs\n\nparse_dacl() limits the attacker-controlled ACE count by comparing it\nwith the number of minimal ACEs that fit in the DACL size. The DACL size\nfield is 16 bits, but the expression subtracts sizeof(struct smb_acl).\nBecause sizeof() is unsigned, a DACL size smaller than the ACL header\nunderflows to a large size_t.\n\nA malicious client can reach this with:\n\nSMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY)\n -\u003e smb2_set_info_sec()\n -\u003e set_info_sec()\n -\u003e parse_sec_desc()\n -\u003e parse_dacl()\n -\u003e init_acl_state(..., 0xffff)\n -\u003e init_acl_state(..., 0xffff)\n -\u003e kmalloc_objs(..., 0xffff)\n\nThus a malformed security descriptor can make num_aces pass the guard\nand drive large temporary ACL state and pointer-array allocations.\n\nReject DACLs smaller than struct smb_acl before doing the subtraction,\nso the ACE count check cannot be bypassed by the underflow."
}
],
"id": "CVE-2026-72382",
"lastModified": "2026-08-17T06:18:42.640",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-15T06:22:11.707",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/16fb65ec15fe7c90f50a2115854bfd9a032d4023"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/282847c0cf22f2e961155ac8e42f6eeab7e16049"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/60908f7ebcd9b6cde74ad5711fab0f49c7970949"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d020e7f27bf65eecd3805404702f716b2b6d9e73"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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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