Heap-based buffer overflow in the iscsiaddnotunderstoodresponse function in drivers/target/iscsi/iscsitarget_parameters.c in the iSCSI target subsystem in the Linux kernel through 3.9.4 allows remote attackers to cause a denial of service (memory corruption and OOPS) or possibly execute arbitrary code via a long key that is not properly handled during construction of an error-response packet.