An issue was discovered in Contiki-NG through 4.3 and Contiki through 3.0. A buffer overflow is present due to an integer underflow during 6LoWPAN fragment processing in the face of truncated fragments in os/net/ipv6/sicslowpan.c. This results in accesses of unmapped memory, crashing the application. An attacker can cause a denial-of-service via a crafted 6LoWPAN frame.