rx/rx.c in OpenAFS 1.5.75 through 1.5.78, 1.6.x before 1.6.15, and 1.7.x before 1.7.33 does not properly initialize padding at the end of an Rx acknowledgement (ACK) packet, which allows remote attackers to obtain sensitive information by (1) conducting a replay attack or (2) sniffing the network.