CVE-2016-5361: programs/pluto/ikev1.c in libreswan before 3.17 retransmits in initial-responder states, which allows remot...

Security readout for executives and security teams

This vulnerability can let an attacker abuse certain Libreswan IKEv1 behavior to create denial-of-service traffic amplification. The business risk is highest where older Libreswan-based VPN or IPsec services are reachable from untrusted networks. The source bundle does not cite active exploitation. Likely exposure is internet-facing VPN or IPsec infrastructure running Libreswan before 3.17 with IKEv1 enabled. Other IKEv1 implementations were expected to receive separate CVEs, so do not assume this specific CVE covers non-Libreswan products without vendor confirmation. Treat this as a targeted availability risk for VPN and IPsec infrastructure, not a data-theft finding. Prioritize patch verification for exposed gateways because disruption there can affect remote access and site-to-site connectivity. Mitigation focus: Upgrade Libreswan to 3.17 or later where applicable.; Apply the relevant vendor security advisory packages, including Red Hat guidance where applicable.; Check vendor guidance for any non-Libreswan IKEv1 implementation..

Prepared

Jun 13, 2026, 14:22 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.