Buffer Overread in odhcpd DHCP Server on OpenWrt Devices

CVE-2026-55606

What is CVE-2026-55606?

A vulnerability exists in the odhcpd DHCP server utilized by OpenWrt, where the self-loop detection process improperly handles the length of the DUID in its network-byte-order representation. This flaw allows a single unauthenticated DHCPv6 packet to lead to a significant buffer overread, exploiting a 128-byte buffer to read up to 2560 bytes, potentially allowing attackers to access sensitive data or cause application instability. Current versions prior to 25.12 are affected, and no patches are available as of the last update.

References