CVE-2026-56116 dhcpcd Memory Leak DoS via IPv6 Router Advertisement Handling

High 7.1 Published 23 Jun 2026 Updated 28 Jul 2026

An unauthenticated attacker can cause a denial of service in dhcpcd by sending crafted IPv6 Router Advertisements that trigger a memory leak.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-56116?

CVE-2026-56116 is a high-severity denial of service vulnerability in NetworkConfiguration dhcpcd, published on 23 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

dhcpcd through 10.3.2, fixed in commit 708b4a5, contains a memory leak vulnerability in the IPv6 Router Advertisement route information handling that allows an unauthenticated same-link attacker to cause denial of service by sending crafted Router Advertisements. Attackers can repeatedly send Router Advertisements containing Route Information options with a lifetime of zero, triggering unfreed allocations in routeinfo_findalloc() that cause linear memory exhaustion and eventual daemon crash.

Weakness: CWE-401

Which versions are affected by CVE-2026-56116?

It affects 1 product.

Products include Dhcpcd Project Dhcpcd.

How do I fix CVE-2026-56116?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-56116 being exploited?

There is no known exploitation of CVE-2026-56116 in the wild and no public exploit code.

Sources

Also known as ALPINE-CVE-2026-56116, AZL-90219, BELL-CVE-2026-56116, DEBIAN-CVE-2026-56116, GHSA-g36w-q35r-qvg3, UBUNTU-CVE-2026-56116.