USN-3171-1: LibVNCServer vulnerabilities

11 January 2017

libvncserver vulnerabilities

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

  • Ubuntu 16.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


Several security issues were fixed in LibVNCServer.

Software Description

  • libvncserver - vnc server library


Josef Gajdusek discovered that the LibVNCServer client library incorrectly handled certain FrameBufferUpdate messages. If a user were tricked into connecting to a malicious server, an attacker could use this issue to cause a denial of service, or possibly execute arbitrary code. (CVE-2016-9941, CVE-2016-9942)

Update instructions

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

Ubuntu 16.10
libvncclient1 - 0.9.10+dfsg-3ubuntu0.16.10.1
libvncserver1 - 0.9.10+dfsg-3ubuntu0.16.10.1
Ubuntu 16.04 LTS
libvncclient1 - 0.9.10+dfsg-3ubuntu0.16.04.1
libvncserver1 - 0.9.10+dfsg-3ubuntu0.16.04.1
Ubuntu 14.04 LTS
libvncserver0 - 0.9.9+dfsg-1ubuntu1.2
Ubuntu 12.04 LTS
libvncserver0 -

To update your system, please follow these instructions:

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