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CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2026-72381

ksmbd: fix use-after-free of fp->owner.name in durable handle owner check

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Status
Published
Published
Updated
Assigning organization
Linux

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 712cdf917e77a6444ce3836874829d770db20ee6 to < fb978d72052704c6b06c6b0f129fcd60b77169f5affected
  • c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d to < 93d4d46bf9d442a12ea87278049ec416962c627faffected
  • 00ce8d6789dae72d042a4522264964c72891ca37 to < 5a5ac2852cd326529d02f778bc1aa6184701f4d7affected
  • 49110a8ce654bbe56bef7c5e44cce31f4b102b8a to < ed98719be41389d416953b8ef9f07a07dfea6b2baffected
  • 49110a8ce654bbe56bef7c5e44cce31f4b102b8a to < 38637163501fd9e2f684b8cd275d0db5d79f37c6affected
  • c908c853f304a4969b5aa10eba0b50350cc65b80affected
  • 6.6.142 to < 6.6.145affected
  • 6.12.92 to < 6.12.97affected
  • 6.18.25 to < 6.18.40affected
  • 7.0.2 to < 7.1affected

Linux Linux

Default version status: affected

  • 7.1affected
  • 0 to < 7.1unaffected
  • 6.6.145 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References