In the TCP implementation (gnrc_tcp) in RIOT through 2019.07, the parser for TCP options does not terminate on all inputs, allowing a denial-of-service, because sys/net/gnrc/transport_layer/tcp/gnrc_tcp_option.c has an infinite loop for an unknown zero-length option.

RIOT through 2019.07 contains a memory leak in the TCP implementation (gnrc_tcp), allowing an attacker to consume all memory available for network packets and thus effectively stopping all network threads from working. This is related to _receive in sys/net/gnrc/transport_layer/tcp/gnrc_tcp_eventloop.c upon receiving an ACK before a SYN.

RIOT RIOT-OS version after commit 7af03ab624db0412c727eed9ab7630a5282e2fd3 contains a Buffer Overflow vulnerability in sock_dns, an implementation of the DNS protocol utilizing the RIOT sock API that can result in Remote code executing. This attack appears to be exploitable via network connectivity.