CVE-2026-56114: Dhcpcd Project Dhcpcd

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

dhcpcd through 10.3.2, fixed in commit 2f00c7b, contains a one-byte stack out-of-bounds write vulnerability in dhcp6_makemessage() in src/dhcp6.c that allows unauthenticated same-link attackers to write beyond a fixed local buffer by serializing an oversized RFC6603 OPTION_PD_EXCLUDE option body. Attackers can send a crafted DHCPv6 ADVERTISE message containing an IA_PD IAPREFIX /0 with a valid OPTION_PD_EXCLUDE using an exclude prefix length of /121 through /128 to trigger the out-of-bounds write and potentially corrupt adjacent stack memory.

Affected products

• Dhcpcd Project Dhcpcd: up to and including 10.3.2

Published 2026-06-23. Last modified 2026-07-14.