=========================================================================
Ubuntu Security Notice USN-4636-1
November 17, 2020

libvncserver, vino vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

LibVNCServer and Vino could be made to crash.

Software Description:
- vino: VNC server for GNOME
- libvncserver: vnc server library

Details:

It was discovered that LibVNCServer incorrectly handled certain internals.
An attacker could possibly use this issue to cause a denial of service.
This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.

Vino package ships with a LibVNCServer source and all listed releases were
affected for this package.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.10:
  vino                            3.22.0-6ubuntu2.1

Ubuntu 20.04 LTS:
  libvncclient1                   0.9.12+dfsg-9ubuntu0.3
  libvncserver1                   0.9.12+dfsg-9ubuntu0.3
  vino                            3.22.0-5ubuntu2.2

Ubuntu 18.04 LTS:
  libvncclient1                   0.9.11+dfsg-1ubuntu1.4
  libvncserver1                   0.9.11+dfsg-1ubuntu1.4
  vino                            3.22.0-3ubuntu1.2

Ubuntu 16.04 LTS:
  libvncclient1                   0.9.10+dfsg-3ubuntu0.16.04.6
  libvncserver1                   0.9.10+dfsg-3ubuntu0.16.04.6
  vino                            3.8.1-0ubuntu9.4

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4636-1
  CVE-2020-25708

Package Information:
  https://launchpad.net/ubuntu/+source/vino/3.22.0-6ubuntu2.1
  https://launchpad.net/ubuntu/+source/libvncserver/0.9.12+dfsg-9ubuntu0.3
  https://launchpad.net/ubuntu/+source/vino/3.22.0-5ubuntu2.2
  https://launchpad.net/ubuntu/+source/libvncserver/0.9.11+dfsg-1ubuntu1.4
  https://launchpad.net/ubuntu/+source/vino/3.22.0-3ubuntu1.2
  https://launchpad.net/ubuntu/+source/libvncserver/0.9.10+dfsg-3ubuntu0.16.04.6
  https://launchpad.net/ubuntu/+source/vino/3.8.1-0ubuntu9.4