ESB-2017.2583 - [Ubuntu] xserver-xorg-core: Multiple vulnerabilities 2017-10-13

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             AUSCERT External Security Bulletin Redistribution

                      X.Org X server vulnerabilities
                              13 October 2017


        AusCERT Security Bulletin Summary

Product:           xserver-xorg-core
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Denial of Service               -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-13723 CVE-2017-13721 

Reference:         ESB-2017.2535

Original Bulletin:

- --------------------------BEGIN INCLUDED TEXT--------------------

Ubuntu Security Notice USN-3453-1
October 12, 2017

xorg-server, xorg-server-hwe-16.04, xorg-server-lts-xenial vulnerabilities

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

- - Ubuntu 17.04
- - Ubuntu 16.04 LTS
- - Ubuntu 14.04 LTS


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

Software Description:
- - xorg-server: X.Org X11 server
- - xorg-server-hwe-16.04: X.Org X11 server
- - xorg-server-lts-xenial: X.Org X11 server


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.

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 LTS:
  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 LTS:
  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.

  CVE-2017-13721, CVE-2017-13723

Package Information:

- --------------------------END INCLUDED TEXT--------------------

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