High [CVE-2026-68381] Use-after-free vulnerability due to race condition in connection handling

In the Linux kernel, the following vulnerability has been resolved: ksmbd: pin conn during async oplock break notification smb2_oplock_break_noti() and smb2_lease_break_noti() store a ksmbd_conn pointer in an async ksmbd_work and then queue that work on ksmbd-io.

The work only increments conn->r_count, which prevents teardown from passing the pending-request wait after the increment, but it does not pin the struct ksmbd_conn object. If connection teardown races with an oplock break notification, the last conn reference can be dropped before the queued worker finishes.

The worker then uses the freed conn in ksmbd_conn_write() and ksmbd_conn_r_count_dec(). Take a real conn reference when publishing the conn pointer to the async work item, and drop it after the notification work has decremented r_count.

Apply the same lifetime rule to lease break notification, which uses the same work->conn pattern. A flaw was found in ksmbd, a Linux kernel module that provides an in-kernel SMB server.

A race condition exists during connection teardown and asynchronous oplock or lease break notifications. This can lead to a use-after-free vulnerability, where a freed connection object is still accessed by a queued worker.

This issue could potentially result in memory corruption, leading to system instability or a denial of service.