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

Releases

• Ubuntu 17.04
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

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

• xserver-xorg-core - 2:1.19.3-1ubuntu1.2

Ubuntu 16.04

• xserver-xorg-core - 2:1.18.4-0ubuntu0.6
• xserver-xorg-core-hwe-16.04 - 2:1.19.3-1ubuntu1~16.04.3

Ubuntu 14.04

• xserver-xorg-core - 2:1.15.1-0ubuntu2.10
• xserver-xorg-core-lts-xenial - 2:1.18.3-1ubuntu2.3~trusty3

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

References

• CVE-2017-13721
• CVE-2017-13723