CVE-2026-34960: barebox Out-of-Bounds Read in DHCP Option Parsing

barebox prior to version 2026.04.0 contains an out-of-bounds read vulnerability in DHCP option parsing within the dhcp_message_type() function that fails to verify the options pointer remains within received packet bounds. An attacker on the same broadcast domain can send a crafted DHCP Offer or ACK packet without a proper 0xff end marker to cause the parser to read past valid packet data and potentially crash the system.