CVE-2026-56113

Medium

Description

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.

SeverityMedium
CVSS5.3
Exploit probability—
ProductDhcpcd
PublishedJun 23, 2026
First seenJun 23, 2026

How to fix

Affected products

ProductAffected versionsFixed in
dhcpcd_project dhcpcdv ≤ 10.3.2—

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