security/vuxml: Record strongswan buffer overflow

strongSwan before 5.9.12 has a buffer overflow and possible unauthenticated
remote code execution via a DH public value that exceeds the internal buffer in
charon-tkm's DH proxy. The earliest affected version is 5.3.0. An attack can
occur via a crafted IKE_SA_INIT message.

NVD score not yet provided.

PR: 275620