Contiki-NG is an open-source, cross-platform operating system for IoT devices. Because of insufficient validation of IPv6 neighbor discovery options in Contiki-NG, attackers can send neighbor solicitation packets that trigger an out-of-bounds read. The problem exists in the module os/net/ipv6/uip-nd6.c, where memory read operations from the main packet buffer, <code>uip_buf</code>, are not checked if they go out of bounds. In particular, this problem can occur when attempting to read the 2-byte option header and the Source Link-Layer Address Option (SLLAO). This attack requires ipv6 be enabled for the network. The problem has been patched in the develop branch of Contiki-NG. The upcoming 4.8 release of Contiki-NG will include the patch.Users unable to upgrade may apply the patch in Contiki-NG PR #1654.