Multiple format string vulnerabilities in isns.c in (1) Linux SCSI target framework (aka tgt or scsi-target-utils) 1.0.3, 0.9.5, and earlier and (2) iSCSI Enterprise Target (aka iscsitarget) 0.4.16 allow remote attackers to cause a denial of service (tgtd daemon crash) or possibly have unspecified other impact via vectors that involve the isns_attr_query and qry_rsp_handle functions, and are related to (a) client appearance and (b) client disappearance messages.