CVE-2026-56117: dhcpcd Heap Use-After-Free via Control Socket Handling
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 controlrecvdata() to free the client object while the same READ+HANGUP event subsequently reaches controlhangup() 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
dhcpcdto a version that resolves this vulnerability.Patch 78ea09e
Event History
Frequently Asked Questions
What is the severity of CVE-2026-56117?
CVE-2026-56117 has a medium severity rating of 5.7.
How do I fix CVE-2026-56117?
To fix CVE-2026-56117, you should update dhcpcd to version 10.3.3 or later, which includes the security fix.
What type of vulnerability is CVE-2026-56117?
CVE-2026-56117 is a heap use-after-free vulnerability that affects the control socket handling in dhcpcd.
Who can exploit CVE-2026-56117?
CVE-2026-56117 can be exploited by local unprivileged attackers if privilege separation is disabled.
What impact does CVE-2026-56117 have?
The impact of CVE-2026-56117 includes potential memory corruption, which can lead to denial of service.