CVE-2016-5361: Libreswan

High severity, CVSS 7.5. EPSS: 2.7% chance of exploitation in the next 30 days.

programs/pluto/ikev1.c in libreswan before 3.17 retransmits in initial-responder states, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed UDP packet. NOTE: the original behavior complies with the IKEv1 protocol, but has a required security update from the libreswan vendor; as of 2016-06-10, it is expected that several other IKEv1 implementations will have vendor-required security updates, with separate CVE IDs assigned to each.

Affected products

• Libreswan Libreswan: up to and including 3.16

Published 2016-06-16. Last modified 2026-06-17.