This indicates an attack attempt to exploit a Buffer Overflow Vulnerability in dhcpcd.
A remote attacker on the local network can exploit this vulnerability by sending a DHCPv6 REPLY containing an IA_NA or IA_TA option with an oversized encapsulated IA Address option. Successful exploitation could result in the execution of arbitrary code in the context of the dhcpcd process which typically runs as the root user.
dhcpcd 7.x prior to 7.2.1
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.