Red Hat Security Advisory: libreswan security update

Libreswan, used for IPsec and IKE on Linux, contains several vulnerabilities that can cause denial of service conditions. CVE-2026-50721 and CVE-2026-50722 describe DoS attacks via RSA-SHA1 authentication payloads in IKEv1 and IKEv2 respectively. CVE-2026-12413 involves a DoS via malformed fragmentation in IKEv2. CVE-2026-14957 is an assertion failure triggered by a badly formatted X.509 certificate, causing the daemon to crash. Red Hat has issued an update for libreswan version 5.3.2-1.el10_2 in Red Hat Enterprise Linux 10 to fix these vulnerabilities.

Successful exploitation of these vulnerabilities can cause denial of service conditions by crashing or disrupting the libreswan daemon, potentially interrupting VPN and secure tunnel services relying on IPsec. There is no indication of remote code execution or data disclosure. The impact is primarily service availability degradation.

Red Hat has released an official security update for libreswan in Red Hat Enterprise Linux 10 (libreswan-5.3.2-1.el10_2) that addresses these vulnerabilities. Users should apply this update promptly to remediate the issues. For detailed update instructions, refer to the Red Hat advisory at https://access.redhat.com/articles/11258. No additional mitigation actions are specified or required beyond applying the update.