Critical severity · published Aug 15, 2026
CVE-2026-72381
ksmbd: fix use-after-free of fp->owner.name in durable handle owner check
9.8
CVSS
0.7%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 51% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
712cdf917e77a6444ce3836874829d770db20ee6 before fb978d72052704c6b06c6b0f129fcd60b77169f5; c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d before 93d4d46bf9d442a12ea87278049ec416962c627f; 00ce8d6789dae72d042a4522264964c72891ca37 before 5a5ac2852cd326529d02f778bc1aa6184701f4d7; 49110a8ce654bbe56bef7c5e44cce31f4b102b8a before ed98719be41389d416953b8ef9f07a07dfea6b2b; 49110a8ce654bbe56bef7c5e44cce31f4b102b8a before 38637163501fd9e2f684b8cd275d0db5d79f37c6; c908c853f304a4969b5aa10eba0b50350cc65b80; +5 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-72381
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-72381
git.kernel.org
https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6
git.kernel.org
https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7
git.kernel.org
https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f
git.kernel.org
https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b
git.kernel.org
https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5
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