CVE-2026-74522 (GCVE-0-2026-74522)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-19 16:38
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free in __close_file_table_ids()
A ksmbd_file can remain alive after logical close while another session
holds a temporary reference obtained through ksmbd_lookup_fd_inode().
ksmbd_close_fd() currently marks the file closed and drops the idr-owned
reference, but leaves the pointer published in the closing session's idr
until the final reference is dropped.
If the foreign holder performs the final ksmbd_fd_put(), __put_fd_final()
supplies the foreign session's file table to __ksmbd_close_fd(). The object
is then freed without being removed from its owner's idr, and the owner
session later dereferences the stale pointer during file-table teardown.
Remove the volatile id from the owner's idr while ksmbd_close_fd() still
holds that table's lock, and clear volatile_id before dropping
the idr-owned reference. A later foreign final put then only performs
physical destruction and cannot remove the object from the wrong table.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 8510a043d334ecdf83d4604782f288db6bf21d60 Version: 8510a043d334ecdf83d4604782f288db6bf21d60 Version: 8510a043d334ecdf83d4604782f288db6bf21d60 Version: 8510a043d334ecdf83d4604782f288db6bf21d60 Version: 8510a043d334ecdf83d4604782f288db6bf21d60 Version: 8510a043d334ecdf83d4604782f288db6bf21d60 Version: df30cbfd3d8a70e61ce59f63ce5ed2261799ac10 Version: aaf1d5ebb358f546414965b39da90107a7ca7ce5 Version: 5.15.38 ≤ Version: 5.17.6 ≤ |
||
{
"containers": {
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{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/server/vfs_cache.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "5.18"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"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": "6.1.183",
"versionStartIncluding": "5.18",
"vulnerable": true
},
{
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},
{
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{
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{
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},
{
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},
{
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"versionStartIncluding": "5.17.6",
"vulnerable": true
}
],
"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 __close_file_table_ids()\n\nA ksmbd_file can remain alive after logical close while another session\nholds a temporary reference obtained through ksmbd_lookup_fd_inode().\nksmbd_close_fd() currently marks the file closed and drops the idr-owned\nreference, but leaves the pointer published in the closing session\u0027s idr\nuntil the final reference is dropped.\n\nIf the foreign holder performs the final ksmbd_fd_put(), __put_fd_final()\nsupplies the foreign session\u0027s file table to __ksmbd_close_fd(). The object\nis then freed without being removed from its owner\u0027s idr, and the owner\nsession later dereferences the stale pointer during file-table teardown.\n\nRemove the volatile id from the owner\u0027s idr while ksmbd_close_fd() still\nholds that table\u0027s lock, and clear volatile_id before dropping\nthe idr-owned reference. A later foreign final put then only performs\nphysical destruction and cannot remove the object from the wrong table."
}
],
"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 bug is in ksmbd, the in-kernel SMB server reached remotely over TCP port 445 via SMB2 CREATE/CLOSE/SET_INFO rename and session teardown requests.\nAC:L - An attacker controls both sides of the race by issuing concurrent SMB2 CLOSE and rename operations on the same share, then logoff or disconnect; no victim-dependent timing or memory layout is required.\nPR:L - Exploitation requires a valid authenticated SMB session and share access to open, close, and rename files; it is not reachable on pre-authentication negotiate/echo paths.\nUI:N - No end-user action is required beyond the attacker driving SMB protocol operations on their own client connection(s).\nS:U - Impact is confined to kernel memory corruption and privilege escalation on the SMB server host; it does not cross a VM, container, or IOMMU security boundary.\nC:H - Use-after-free of a freed ksmbd_file slab object during session file-table teardown enables reading attacker-influenced heap contents and building arbitrary kernel memory read primitives.\nI:H - The UAF corrupts kernel heap metadata and ksmbd_file fields (pointers, list heads), enabling heap grooming and arbitrary write or control-flow hijack for code execution as root.\nA:H - The stale IDR entry is dereferenced during __close_file_table_ids() on logoff, tree disconnect, or connection teardown, causing kernel oops/panic and repeatable remote denial of service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:38:25.036Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/19bfd90d5aaf63217735d81964585c5306158e5f"
},
{
"url": "https://git.kernel.org/stable/c/67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd"
},
{
"url": "https://git.kernel.org/stable/c/0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac"
},
{
"url": "https://git.kernel.org/stable/c/9be4a66f019ea90bd9deca70511f4f9ffebf5c6f"
},
{
"url": "https://git.kernel.org/stable/c/cffbdc86393b0235383a20c8c59bc32f16036459"
},
{
"url": "https://git.kernel.org/stable/c/e7188199eff46a636f3436356f0aae039be6dd66"
}
],
"title": "ksmbd: fix use-after-free in __close_file_table_ids()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74522",
"datePublished": "2026-08-15T12:27:39.945Z",
"dateReserved": "2026-08-15T05:44:03.911Z",
"dateUpdated": "2026-08-19T16:38:25.036Z",
"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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