CVE-2026-72381 (GCVE-0-2026-72381)
Vulnerability from cvelistv5
Published
2026-08-15 05:56
Modified
2026-08-17 05:43
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free of fp->owner.name in durable handle owner check
Two concurrent SMB2 durable reconnects (DH2C/DHnC) on the same
persistent_id race the fp->owner.name compare-read in
ksmbd_vfs_compare_durable_owner() against the kfree() in
ksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a
standalone kstrdup() buffer whose lifetime is independent of the fp
refcount, and the two sites share no lock: the compare reads the buffer
while the reopen frees it, so the strcmp() can dereference freed memory.
Commit 7ce4fc40018d ("ksmbd: fix durable reconnect double-bind race in
ksmbd_reopen_durable_fd") made the fp->conn claim atomic under
global_ft.lock (closing the owner.name double-free and the ksmbd_file
write-UAF), but the compare-read versus reopen-free pair was left
unserialized.
BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80
Read of size 1 by task kworker
strcmp
ksmbd_vfs_compare_durable_owner
smb2_check_durable_oplock
smb2_open
Freed by task kworker:
kfree
ksmbd_reopen_durable_fd
smb2_open
Allocated by task kworker:
kstrdup
session_fd_check
smb2_session_logoff
The buggy address belongs to the cache kmalloc-8
Serialize both sides of the race with fp->f_lock. The global durable
file-table lock still protects the durable reconnect claim, but
fp->owner.name is per-open state and does not need to block unrelated
durable table lookups or reconnects. The teardown is left at its
existing location after the reopen-success point so that an __open_id()
rollback still retains owner.name for a later legitimate reconnect to
verify.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 712cdf917e77a6444ce3836874829d770db20ee6 Version: c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d Version: 00ce8d6789dae72d042a4522264964c72891ca37 Version: 49110a8ce654bbe56bef7c5e44cce31f4b102b8a Version: 49110a8ce654bbe56bef7c5e44cce31f4b102b8a Version: c908c853f304a4969b5aa10eba0b50350cc65b80 Version: 6.6.142 ≤ Version: 6.12.92 ≤ Version: 6.18.25 ≤ Version: 7.0.2 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/server/vfs_cache.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "fb978d72052704c6b06c6b0f129fcd60b77169f5",
"status": "affected",
"version": "712cdf917e77a6444ce3836874829d770db20ee6",
"versionType": "git"
},
{
"lessThan": "93d4d46bf9d442a12ea87278049ec416962c627f",
"status": "affected",
"version": "c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d",
"versionType": "git"
},
{
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"status": "affected",
"version": "00ce8d6789dae72d042a4522264964c72891ca37",
"versionType": "git"
},
{
"lessThan": "ed98719be41389d416953b8ef9f07a07dfea6b2b",
"status": "affected",
"version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a",
"versionType": "git"
},
{
"lessThan": "38637163501fd9e2f684b8cd275d0db5d79f37c6",
"status": "affected",
"version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a",
"versionType": "git"
},
{
"status": "affected",
"version": "c908c853f304a4969b5aa10eba0b50350cc65b80",
"versionType": "git"
},
{
"lessThan": "6.6.145",
"status": "affected",
"version": "6.6.142",
"versionType": "semver"
},
{
"lessThan": "6.12.97",
"status": "affected",
"version": "6.12.92",
"versionType": "semver"
},
{
"lessThan": "6.18.40",
"status": "affected",
"version": "6.18.25",
"versionType": "semver"
},
{
"lessThan": "7.1",
"status": "affected",
"version": "7.0.2",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"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": "7.1"
},
{
"lessThan": "7.1",
"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"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.145",
"versionStartIncluding": "6.6.142",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.97",
"versionStartIncluding": "6.12.92",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "6.18.25",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
"versionStartIncluding": "7.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "7.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "7.0.2",
"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 of fp-\u003eowner.name in durable handle owner check\n\nTwo concurrent SMB2 durable reconnects (DH2C/DHnC) on the same\npersistent_id race the fp-\u003eowner.name compare-read in\nksmbd_vfs_compare_durable_owner() against the kfree() in\nksmbd_reopen_durable_fd()\u0027s reopen-success path. fp-\u003eowner.name is a\nstandalone kstrdup() buffer whose lifetime is independent of the fp\nrefcount, and the two sites share no lock: the compare reads the buffer\nwhile the reopen frees it, so the strcmp() can dereference freed memory.\n\nCommit 7ce4fc40018d (\"ksmbd: fix durable reconnect double-bind race in\nksmbd_reopen_durable_fd\") made the fp-\u003econn claim atomic under\nglobal_ft.lock (closing the owner.name double-free and the ksmbd_file\nwrite-UAF), but the compare-read versus reopen-free pair was left\nunserialized.\n\n BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80\n Read of size 1 by task kworker\n strcmp\n ksmbd_vfs_compare_durable_owner\n smb2_check_durable_oplock\n smb2_open\n Freed by task kworker:\n kfree\n ksmbd_reopen_durable_fd\n smb2_open\n Allocated by task kworker:\n kstrdup\n session_fd_check\n smb2_session_logoff\n The buggy address belongs to the cache kmalloc-8\n\nSerialize both sides of the race with fp-\u003ef_lock. The global durable\nfile-table lock still protects the durable reconnect claim, but\nfp-\u003eowner.name is per-open state and does not need to block unrelated\ndurable table lookups or reconnects. The teardown is left at its\nexisting location after the reopen-success point so that an __open_id()\nrollback still retains owner.name for a later legitimate reconnect to\nverify."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The flaw is reached via ksmbd\u0027s in-kernel SMB2 server on TCP port 445; remote SMB2_CREATE durable-handle reconnect packets (DH2C/DHnC) traverse ksmbd_conn_handler_loop() -\u003e smb2_check_user_session() -\u003e smb2_open() -\u003e parse_durable_handle_context() -\u003e smb2_check_durable_oplock() / ksmbd_reopen_durable_fd().\nAC:L - The attacker controls both sides of the race by opening a durable handle, issuing SMB2_LOGOFF to preserve owner.name via session_fd_check(), then sending concurrent SMB2_CREATE durable reconnect requests for the same persistent_id from multiple connections; no timing or layout outside attacker control is required.\nPR:N - Exploitation requires only network reachability to ksmbd and valid SMB session credentials (guest or any share user) plus tree connect; no elevated host privileges, capabilities, or local access are needed beyond share-level SMB access obtainable through the protocol itself.\nUI:N - No victim user interaction is required beyond a server running ksmbd with durable handles enabled; the attacker programmatically drives the open, logoff, and concurrent reconnect SMB2 sequence over the network.\nS:U - Impact is confined to kernel heap memory corruption and privilege escalation within the same host security authority; this is not a VM escape, container boundary bypass, or IOMMU/DMA isolation break.\nC:H - strcmp() in ksmbd_vfs_compare_durable_owner() dereferences a freed kmalloc-8 fp-\u003eowner.name buffer while a concurrent ksmbd_reopen_durable_fd() kfree() runs; this slab use-after-free enables arbitrary kernel memory disclosure via heap reuse.\nI:H - Use-after-free of the standalone owner.name kstrdup buffer provides kernel heap corruption primitives; with heap grooming the freed slab can be reallocated for arbitrary kernel memory writes and control-flow hijacking.\nA:H - KASAN reports slab-use-after-free in strcmp on the owner.name buffer during concurrent smb2_open durable reconnects; the UAF can trigger kernel oops or panic on ksmbd worker threads and is repeatable by resending concurrent reconnect requests."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:43:32.020Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5"
},
{
"url": "https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f"
},
{
"url": "https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7"
},
{
"url": "https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b"
},
{
"url": "https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6"
}
],
"title": "ksmbd: fix use-after-free of fp-\u003eowner.name in durable handle owner check",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72381",
"datePublished": "2026-08-15T05:56:13.477Z",
"dateReserved": "2026-08-09T03:40:39.923Z",
"dateUpdated": "2026-08-17T05:43:32.020Z",
"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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