A ssvnc security update has been released for Debian GNU/Linux 8 LTS

Package : ssvnc
Version : 1.0.29-2+deb8u1
CVE ID : CVE-2018-20020 CVE-2018-20021 CVE-2018-20022 CVE-2018-20024
Debian Bug : 945827

Several vulnerabilities have been identified in the VNC code of ssvnc, an
encryption-capable VNC client..

The vulnerabilities referenced below are issues that have originally been
reported against Debian source package libvncserver (which also ships the
libvncclient shared library). The ssvnc source package in Debian ships a
custom-patched, stripped down and outdated variant of libvncclient, thus
some of libvncclient's security fixes required porting over.

CVE-2018-20020

LibVNC contained heap out-of-bound write vulnerability inside
structure in VNC client code that can result remote code execution

CVE-2018-20021

LibVNC contained a CWE-835: Infinite loop vulnerability in VNC client
code. Vulnerability allows attacker to consume excessive amount of
resources like CPU and RAM

CVE-2018-20022

LibVNC contained multiple weaknesses CWE-665: Improper Initialization
vulnerability in VNC client code that allowed attackers to read stack
memory and could be abused for information disclosure. Combined with
another vulnerability, it could be used to leak stack memory layout
and in bypassing ASLR.

CVE-2018-20024

LibVNC contained null pointer dereference in VNC client code that
could result DoS.

For Debian 8 "Jessie", these problems have been fixed in version
1.0.29-2+deb8u1.

We recommend that you upgrade your ssvnc packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS