A flaw was discovered in coturn, a TURN and STUN server for VoIP. By
default coturn does not allow peers on the loopback addresses
(127.x.x.x and ::1). A remote attacker can bypass the protection via a specially crafted request using a peer address of '0.0.0.0' and trick
coturn in relaying to the loopback interface. If listening on IPv6 the
loopback interface can also be reached by using either [::1] or [::] as
For the stable distribution (buster), this problem has been fixed in
We recommend that you upgrade your coturn packages.