CVE-2026-64392 (GCVE-0-2026-64392)
Vulnerability from cvelistv5
Published
2026-07-25 08:50
Modified
2026-08-17 04:54
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for delete-on-close
Delete-on-close can be completed by deferred or durable handle teardown,
where no request work is available. Both the base-file unlink and the ADS
xattr removal consequently run with the ksmbd worker credentials and can
bypass filesystem permission checks.
Run both operations with the credentials captured in struct file when the
handle was opened. This preserves the authenticated user's fsuid, fsgid,
supplementary groups and capability restrictions at final close.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/server/vfs.c",
"fs/smb/server/vfs_cache.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "f08b3f451f12eee4abd8a5981803bc36db84458b",
"status": "affected",
"version": "f44158485826c076335d6860d35872271a83791d",
"versionType": "git"
},
{
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"status": "affected",
"version": "f44158485826c076335d6860d35872271a83791d",
"versionType": "git"
},
{
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"status": "affected",
"version": "f44158485826c076335d6860d35872271a83791d",
"versionType": "git"
},
{
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"status": "affected",
"version": "f44158485826c076335d6860d35872271a83791d",
"versionType": "git"
},
{
"lessThan": "52e2f21911158ec961cd5aae19c56460db382af0",
"status": "affected",
"version": "f44158485826c076335d6860d35872271a83791d",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/smb/server/vfs.c",
"fs/smb/server/vfs_cache.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": "6.12.96",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.4",
"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": "6.6.145",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.96",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.39",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.4",
"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: use opener credentials for delete-on-close\n\nDelete-on-close can be completed by deferred or durable handle teardown,\nwhere no request work is available. Both the base-file unlink and the ADS\nxattr removal consequently run with the ksmbd worker credentials and can\nbypass filesystem permission checks.\n\nRun both operations with the credentials captured in struct file when the\nhandle was opened. This preserves the authenticated user\u0027s fsuid, fsgid,\nsupplementary groups and capability restrictions at final close."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - A remote SMB client reaches the vulnerable CREATE, SET_INFO, and CLOSE paths through ksmbd over TCP/445.\nAC:L - The attacker can deterministically request delete-on-close and close or disconnect the handle; no race or condition outside attacker control is required.\nPR:N - Although a valid SMB session and writable tree are required, ksmbd supports anonymous guest sessions, making exploitation possible without prior privileges on a reasonably configured writable guest share.\nUI:N - Exploitation requires only attacker-generated SMB requests and no action by another user.\nS:U - The unauthorized filesystem operations occur within the same host and kernel security authority, without crossing a VM, sandbox, or IOMMU boundary.\nC:N - The flaw only unlinks filesystem objects or removes ADS xattrs; it provides no read primitive, information disclosure, or memory corruption.\nI:H - The privileged worker can delete attacker-selected files, empty directories, or ADS data despite the opener\u0027s filesystem restrictions, permitting complete destruction or replacement of protected exported data.\nA:H - The attacker can repeatedly and recursively delete exported resources, potentially causing complete loss of critical share data or services that depend on it."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:54:44.931Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/f08b3f451f12eee4abd8a5981803bc36db84458b"
},
{
"url": "https://git.kernel.org/stable/c/18c59109bb6fb816d5102171666f87cf1e29901d"
},
{
"url": "https://git.kernel.org/stable/c/e72c15085b6d86f45d224d98aa75b5cace4aaab9"
},
{
"url": "https://git.kernel.org/stable/c/4b7059974549d278e30fe70e2a4e421f9839817d"
},
{
"url": "https://git.kernel.org/stable/c/52e2f21911158ec961cd5aae19c56460db382af0"
}
],
"title": "ksmbd: use opener credentials for delete-on-close",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64392",
"datePublished": "2026-07-25T08:50:38.634Z",
"dateReserved": "2026-07-19T15:36:31.785Z",
"dateUpdated": "2026-08-17T04:54:44.931Z",
"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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