Incorrect access controls in res_srtp.c in Sangoma Asterisk 13.38.1, 16.16.0, 17.9.1, and 18.2.0 and Certified Asterisk 16.8-cert5 allow a remote unauthenticated attacker to prematurely terminate secure calls by replaying SRTP packets.
An unauthenticated remote attacker could replay SRTP packets which could cause an Asterisk instance configured without strict RTP validation to tear down calls prematurely.