Buffer overflow in Dhcpcd Project
CVE-2026-56114
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.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (19.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Dhcpcd_project Dhcpcd
- Networkconfiguration Dhcpcd — versions 0, 2f00c7bfc408b6582d331932dfa47829c4819029
Weakness classification (CWE)
References
- disclosure@vulncheck.com (Patch, patch)
- disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-56114?
- CVE-2026-56114 is a medium-severity vulnerability in Dhcpcd Project, classified under Out-of-bounds Write. CVSS score: 5.3/10. Published 2026-06-23.
- How severe is CVE-2026-56114?
- Medium severity. CVSS v3 base score is 5.3 out of 10.