The Libreswan Project was notified of an issue causing libreswan to restart when using IKEv1 without specifying an esp= line. When the peer requests AES-GMAC, libreswan's default proposal handler causes an assertion failure and crashes and restarts. IKEv2 connections are not affected.
Severity
CVSS 3.1
6.5 medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
0.8% chance of exploitation in the next 30 days; higher than 56% of CVEs (scores of 2026-10-31)