A vulnerability in the Linux kernel's iSCSI implementation allows improper validation of the Initiator Task Tag (ITT) reflected in a Reject Protocol Data Unit (PDU). This can lead to the completion of in-flight SCSI commands incorrectly, potentially causing data corruption or kernel crashes. The issue arises because the ITT value from the target is not properly validated before being used to identify tasks, leading to possible reference count underflows and null pointer dereferences.