In stroke_socket.c in strongSwan before 5.6.3, a missing packet length check could allow a buffer underflow, which may lead to resource exhaustion and denial of service while reading from the socket.
lists.opensuse.org/opensuse-security-announce/2019-11/msg00077.html
lists.opensuse.org/opensuse-security-announce/2019-12/msg00001.html
lists.opensuse.org/opensuse-security-announce/2020-03/msg00047.html
packetstormsecurity.com/files/172833/strongSwan-VPN-Charon-Server-Buffer-Overflow.html
www.kb.cert.org/vuls/id/338343
www.securityfocus.com/bid/104263
git.strongswan.org/?p=strongswan.git%3Ba=commitdiff%3Bh=0acd1ab4
security.gentoo.org/glsa/201811-16
usn.ubuntu.com/3771-1/
www.debian.org/security/2018/dsa-4229