USN-3453-1: X.Org X server vulnerabilities

12 October 2017

Several security issues were fixed in the X.Org X server.

Releases

Packages

  • xorg-server - X.Org X11 server
  • xorg-server-hwe-16.04 - X.Org X11 server
  • xorg-server-lts-xenial - X.Org X11 server

Details

Michal Srb discovered that the X.Org X server incorrectly handled shared
memory segments. An attacker able to connect to an X server, either locally
or remotely, could use this issue to crash the server, or possibly replace
shared memory segments of other X clients in the same session.
(CVE-2017-13721)

Michal Srb discovered that the X.Org X server incorrectly handled XKB
buffers. An attacker able to connect to an X server, either locally or
remotely, could use this issue to crash the server, or possibly execute
arbitrary code. (CVE-2017-13723)

Update instructions

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

Ubuntu 17.04
Ubuntu 16.04
Ubuntu 14.04

After a standard system update you need to reboot your computer to make
all the necessary changes.