In 2006 EPCglobal and the International Organization for Standards (ISO) ratified the EPC Class-1 Generation-2 (Gen-2) and the ISO 18000-6C standards , respectively. These efforts represented major advancements in the direction of universal standardization for low-cost RFID tags. However, a cause for concern is that security issues do not seem to be properly addressed. In this paper, we propose a new lightweight RFID tag-reader mutual authentication scheme for use under the EPCglobal framework. The scheme is based on previous work by Konidala and Kim . We attempt to mitigate the weaknesses observed in the original scheme and, at the same time, consider other possible adversarial threats as well as constraints on low-cost RFID tags requirements.