USN-3618-1: LibVNCServer vulnerability

4 April 2018

libvncserver vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 17.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS


LibVNCServer could be made to crash, expose sensitive information, or run programs if it received specially crafted network traffic.

Software Description

  • libvncserver - vnc server library


It was discovered that LibVNCServer incorrectly handled certain packet lengths. A remote attacker able to connect to a LibVNCServer could possibly use this issue to obtain sensitive information, cause a denial of service, or execute arbitrary code.

Update instructions

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

Ubuntu 17.10
libvncclient1 - 0.9.11+dfsg-1ubuntu0.1
libvncserver1 - 0.9.11+dfsg-1ubuntu0.1
Ubuntu 16.04 LTS
libvncserver1 - 0.9.10+dfsg-3ubuntu0.16.04.2
Ubuntu 14.04 LTS
libvncserver0 - 0.9.9+dfsg-1ubuntu1.3

To update your system, please follow these instructions:

After a standard system update you need to restart LibVNCServer applications to make all the necessary changes.