LibVNC before commit a83439b9fbe0f03c48eb94ed05729cb016f8b72f contains multiple heap out-of-bound write vulnerabilities in VNC client code that can result remote code execution
https://www.debian.org/security/2019/dsa-4383
https://usn.ubuntu.com/4587-1/
https://usn.ubuntu.com/4547-1/
https://usn.ubuntu.com/3877-1/
https://security.gentoo.org/glsa/201908-05
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf