CVE-2026-68381
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel, the SMB server (ksmbd) has a use-after-free vulnerability during asynchronous oplock break notification. The pointer to the ksmbd_conn structure is stored in an async work without proper reference counting, which can lead to access to freed memory.
Risk Assessment
An attacker could cause a system crash or potentially execute code in kernel context, posing a serious security threat.
Recommendation
Apply a Linux kernel update containing the fix that takes a real reference on the conn structure before publishing the pointer to the async work.
Original NVD description (English source)
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.