CVE-2026-56117 dhcpcd Heap Use-After-Free via Control Socket Handling

Medium 5.7 Published 23 Jun 2026 Updated 28 Jul 2026

Local attackers can trigger a use-after-free in dhcpcd control socket handling when privilege separation is disabled, potentially leading to code execution or privilege escalation.

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

What is CVE-2026-56117?

CVE-2026-56117 is a medium-severity use after free 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 78ea09e, contains a heap use-after-free vulnerability in the control socket handling within src/control.c that allows local unprivileged attackers to trigger memory corruption when privilege separation is disabled. Attackers can connect to the control socket and send a privileged command such as -x, causing control_recvdata() to free the client object while the same READ+HANGUP event subsequently reaches control_hangup() with the stale pointer, resulting in a use-after-free condition exploitable in deployments using --disable-privsep or where privsep initialization has failed with the control socket operating in mode 0666.

Weakness: CWE-416

Which versions are affected by CVE-2026-56117?

It affects 1 product.

Products include Dhcpcd Project Dhcpcd.

How do I fix CVE-2026-56117?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-56117 being exploited?

There is no known exploitation of CVE-2026-56117 in the wild and no public exploit code.

Sources

Also known as ALPINE-CVE-2026-56117, AZL-90222, BELL-CVE-2026-56117, DEBIAN-CVE-2026-56117, GHSA-p284-r695-7gxf, UBUNTU-CVE-2026-56117.