CVE-2026-80926

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free in oplock break notification

smb2 oplock break noti() reads opinfo->conn without any lock and dereferences it after two allocations which may sleep. When the durable handle owning the oplock is disconnected, session fd check() clears opinfo->conn and drops its conn reference under ci->m lock, and the last ksmbd conn put() frees the connection. A break triggered by another connection that races with the teardown can then resurrect the freed connection: ksmbd conn get() is a plain atomic inc, and the queued break work later dereferences the stale conn via ksmbd conn write(), a use-after-free reachable by any authenticated client holding a durable batch oplock.

Thread the caller's inode into the notification path instead of taking a new reference on it. Every caller of oplock break() already holds a live ksmbd file (or an explicit ksmbd inode lookup lock() reference, in the parent lease break paths) on the inode that owns the break target's oplock list, so ci cannot be freed during the call, and its lock can be taken without dereferencing opinfo->o fp, which a concurrent close may free. Select and pin the connection under ci->m lock, the same lock session fd check() and ksmbd reopen durable fd() use to update opinfo->conn, so a concurrent detach either loses the race to the clear or keeps the connection alive until the notification work releases it. Transfer the reference to the work item and release it on allocation failures.