tinc before 1.0.30 has a broken authentication protocol, without even a partial mitigation.

tinc 1.0.30 through 1.0.34 has a broken authentication protocol, although there is a partial mitigation. This is fixed in 1.1.

Missing message authentication in the meta-protocol in Tinc VPN version 1.0.34 and earlier allows a man-in-the-middle attack to disable the encryption of VPN packets.

Stack-based buffer overflow in the receive_tcppacket function in net_packet.c in tinc before 1.0.21 and 1.1 before 1.1pre7 allows remote authenticated peers to cause a denial of service (crash) or possibly execute arbitrary code via a large TCP packet.