NetBSD cryptodev Race Condition Double-Free via cryptodev_op()

NetBSD prior to commit ec8451e contains a race condition vulnerability in cryptodev_op() within the opencrypto subsystem that allows local attackers to trigger a double-free condition by concurrently issuing CIOCCRYPT operations on the same session identifier on SMP systems. Attackers can exploit mutable per-operation state embedded in the csession struct to corrupt kernel heap memory.