Out-of-bounds read when decoding SNMP messages in Contiki-NG

Contiki-NG is an open-source, cross-platform operating system for IoT devices. An out-of-bounds read of 1 byte can be triggered when sending a packet to a device running the Contiki-NG operating system with SNMP enabled. The SNMP module is disabled in the default Contiki-NG configuration. The vulnerability exists in the os/net/app-layer/snmp/snmp-message.c module, where the snmp_message_decode function fails to check the boundary of the message buffer when reading a byte from it immediately after decoding an object identifier (OID). The problem has been patched in Contiki-NG pull request 2937. It will be included in the next release of Contiki-NG. Users are advised to either apply the patch manually or to wait for the next release. A workaround is to disable the SNMP module in the Contiki-NG build configuration.