Bug 2491845 (CVE-2026-56117)

Summary: CVE-2026-56117 dhcpcd: dhcpcd: Local heap use-after-free vulnerability leads to denial of service.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in dhcpcd. A heap use-after-free vulnerability in the control socket handling allows a local unprivileged attacker to trigger memory corruption. This occurs when privilege separation is disabled, enabling the attacker to send a privileged command to the control socket. Successful exploitation can lead to a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2492027, 2492028    
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Description OSIDB Bzimport 2026-06-23 17:05:46 UTC 
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.