CVE-2023-31129 Information

Description

The Contiki-NG operating system versions 4.8 and prior can be triggered to dereference a NULL pointer in the message handling code for IPv6 router solicitiations. Contiki-NG contains an implementation of IPv6 Neighbor Discovery (ND) in the module os/net/ipv6/uip-nd6.c. The ND protocol includes a message type called Router Solicitation (RS) which is used to locate routers and update their address information via the SLLAO (Source Link-Layer Address Option). If the indicated source address changes a given neighbor entry is set to the STALE state.

The message handler does not check for RS messages with an SLLAO that indicates a link-layer address change that a neighbor entry can actually be created for the indicated address. The resulting pointer is used without a check leading to the dereference of a NULL pointer of type uip_ds6_nbr_t.

The problem has been patched in the develop branch of Contiki-NG and will be included in the upcoming 4.9 release. As a workaround users can apply Contiki-NG pull request 2271 to patch the problem directly.

Reference

https://github.com/contiki-ng/contiki-ng/pull/2271 https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-x29r-5qjg-75mq