CVEvulnerability
CVE-2026-90162
8.8 HIGH
Official page ↗
- Status
- Received
- Published
- 2026-09-17
- Last modified
- 2026-10-21
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- CVSS 3.1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)
- 8.8 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: defer publishing granted locks to prevent UAF/double-free race
In smb2_lock(), mid-batch granted locks are published to connection-wide
(conn->lock_list) and file-wide (fp->lock_list) lists immediately upon
vfs_lock_file() success, while also remaining tracked on the stack-local
rollback_list.
If a subsequent element in the same SMB2_LOCK request array fails
validation or execution, the thread jumps to out: and walks
rollback_list to undo previously granted locks. However, because the
granted lock was already published to conn->lock_list, a concurrent
UNLOCK request on the same connection can find the lock object and
kfree() it before the rollback loop executes.
When the granting thread subsequently walks rollback_list, it
dereferences and frees the already-freed ksmbd_lock structure, resulting
in a Use-After-Free and Double-Free (on both ksmbd_lock and struct
file_lock).
Fix this by deferring the publication of granted locks to
conn->lock_list and fp->lock_list until after the entire array of lock
elements has been processed without error. Mid-batch grants remain
tracked exclusively on the request-local rollback_list until the whole
batch succeeds, eliminating the race window.
References
- https://git.kernel.org/stable/c/29f74f0f2e6df3b393b7b66e810136d0c64e3c59 git.kernel.org
- https://git.kernel.org/stable/c/65f54ed0289e9a57e6c60b14347ccea4c318f1fc git.kernel.org
- https://git.kernel.org/stable/c/a1d26dfb32919088e3638dca01068df3c4507433 git.kernel.org
- https://git.kernel.org/stable/c/b68d4bb6b03a667c305626bd2c242fd162bac17e git.kernel.org
- https://git.kernel.org/stable/c/ff6870cf3b7eccc69d03cbb6f23e3995d96e9a8d git.kernel.org