The Xvnc server in TigerVNC allows remote attackers to cause a denial of service (invalid memory access and crash) by terminating a TLS handshake early.
https://security.gentoo.org/glsa/201801-13
https://access.redhat.com/errata/RHSA-2017:2000
http://www.securityfocus.com/bid/96012
http://www.openwall.com/lists/oss-security/2017/02/02/22
http://rhn.redhat.com/errata/RHSA-2017-0630.html
http://lists.opensuse.org/opensuse-security-announce/2017-02/msg00020.html