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.

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4686-1 dhcpcd5 security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 28 Jul 2026 02:30:00 +0000

Type Values Removed Values Added
First Time appeared Dhcpcd Project
Dhcpcd Project dhcpcd
CPEs cpe:2.3:a:dhcpcd_project:dhcpcd:*:*:*:*:*:*:*:*
Vendors & Products Dhcpcd Project
Dhcpcd Project dhcpcd

Wed, 24 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 24 Jun 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Tue, 23 Jun 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Networkconfiguration
Networkconfiguration dhcpcd
Vendors & Products Networkconfiguration
Networkconfiguration dhcpcd

Tue, 23 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
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.
Title dhcpcd Stack Out-of-Bounds Write in dhcp6_makemessage()
Weaknesses CWE-787
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-07-28T01:49:42.486Z

Reserved: 2026-06-18T19:15:10.650Z

Link: CVE-2026-56114

cve-icon Vulnrichment

Updated: 2026-06-24T14:02:54.637Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-06-23T16:08:10Z

Links: CVE-2026-56114 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-24T11:15:04Z

Weaknesses