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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.6 / Impact : 3.6

Attack Vector ADJACENT_NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/NetworkConfiguration/dhcpcd/commit/2f00c7bfc408b6582d331932dfa47829c4819029	Patch
https://www.vulncheck.com/advisories/dhcpcd-stack-out-of-bounds-write-in-dhcp6-makemessage	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:dhcpcd_project:dhcpcd:*:*:*:*:*:*:*:*

History

25 Oct 2026, 23:10

Type	Values Removed	Values Added
Summary		(es) dhcpcd hasta 10.3.2, corregido en el commit 2f00c7b, contiene una vulnerabilidad de escritura fuera de límites de pila de un byte en dhcp6_makemessage() en src/dhcp6.c que permite a atacantes no autenticados en el mismo enlace escribir más allá de un búfer local fijo serializando un cuerpo de opción RFC6603 OPTION_PD_EXCLUDE sobredimensionado. Los atacantes pueden enviar un mensaje DHCPv6 ADVERTISE manipulado que contiene un IA_PD IAPREFIX /0 con un OPTION_PD_EXCLUDE válido utilizando una longitud de prefijo de exclusión de /121 a /128 para activar la escritura fuera de límites y potencialmente corromper la memoria de pila adyacente.

Information

Published : 2026-06-23 17:17

Updated : 2026-10-25 23:10

NVD link : CVE-2026-56114

Mitre link : CVE-2026-56114

CVE.ORG link : CVE-2026-56114

JSON object : View

Products Affected

dhcpcd_project

dhcpcd

CWE

CWE-787

Out-of-bounds Write

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