CVE-2026-56113

dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION_PD_EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6_deprecatedele() to free a delegated child address while an outer TAILQ_FOREACH_SAFE iterator in dhcp6_deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ_REMOVE is reached.

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/5733d3c59a5651f64357ac11c98b4f39895c8d25	Patch
https://www.vulncheck.com/advisories/dhcpcd-heap-use-after-free-in-dhcp6-deprecateaddrs-via-dhcpv6-renew	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 la versión 10.3.2, corregido en el commit 5733d3c, contiene una vulnerabilidad de uso después de liberación en el heap que permite a atacantes no autenticados en el mismo enlace bloquear el demonio enviando una respuesta DHCPv6 RENEW manipulada con RFC6603 OPTION_PD_EXCLUDE y con ambas duraciones preferida y válida establecidas a cero. Atacantes que actúan como o suplantan a un servidor DHCPv6 pueden activar dhcp6_deprecatedele() para liberar una dirección secundaria delegada mientras un iterador TAILQ_FOREACH_SAFE externo en dhcp6_deprecateaddrs() aún mantiene el puntero liberado, causando un uso después de liberación cuando se alcanza TAILQ_REMOVE.

Information

Published : 2026-06-23 17:17

Updated : 2026-10-25 23:10

NVD link : CVE-2026-56113

Mitre link : CVE-2026-56113

CVE.ORG link : CVE-2026-56113

JSON object : View

Products Affected

dhcpcd_project

dhcpcd

CWE

CWE-416

Use After Free

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