Vulnerability · Published Jun 23, 2026 · Assigned by VulnCheck
CVE-2026-56114dhcpcd Stack Out-of-Bounds Write in dhcp6_makemessage()
Medium 5.3
In plain English
A medium-severity out-of-bounds write in dhcpcd from NetworkConfiguration. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | dhcpcd | 10.5.2-r0 | ALPINE-CVE-2026-56114 |
| Alpine:v3.24 | dhcpcd | 10.5.2-r0 | ALPINE-CVE-2026-56114 |
| Debian:13 | dhcpcd | 1:10.1.0-11+deb13u3 | DEBIAN-CVE-2026-56114 |
| Debian:14 | dhcpcd | 1:10.3.2-4 | DEBIAN-CVE-2026-56114 |
| Debian:12 | dhcpcd5 | 9.4.1-24~deb12u5 | DEBIAN-CVE-2026-56114 |
| Ubuntu:24.04:LTS | dhcpcd | no fix listed | UBUNTU-CVE-2026-56114 |
| Ubuntu:25.10 | dhcpcd | no fix listed | UBUNTU-CVE-2026-56114 |
| Ubuntu:26.04:LTS | dhcpcd | no fix listed | UBUNTU-CVE-2026-56114 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NetworkConfiguration | dhcpcd | 0 – through 10.3.2 |
Weakness: CWE-787 · Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H