CVE-2026-56116
MEDIUMdhcpcd 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…
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.
Affected Products
dhcpcddhcpcd_projectDetection & mitigation playbook
Vendor / applianceDetect
Inventory every dhcpcd_project dhcpcd deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2026-56116 yet — track the dhcpcd_project dhcpcd advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-56116 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2026-56116. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-56116 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-56116 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.